Nano-Micro Letters

High-Performance Gate-All-Around Field Effect Transistors Based on Orderly Arrays of Catalytic Si Nanowire Channels

2025-02-21T09:43:34+00:00

Gate-all-around field-effect transistors (GAA-FETs) represent the leading-edge channel architecture for constructing state-of-the-art high-performance FETs. Despite the advantages offered by the GAA configuration, its application to catalytic silicon nanowire (SiNW) channels, known for facile low-temperature fabrication and high yield, has faced challenges primarily due to issues with precise positioning and alignment. In exploring this promising avenue, we employed an in-plane solid–liquid-solid (IPSLS) growth technique to batch-fabricate orderly arrays of ultrathin SiNWs, with diameters of D_NW = 22.4 ± 2.4 nm and interwire spacing of 90 nm. An in situ channel-releasing technique has been developed to well preserve the geometry integrity of suspended SiNW arrays. By optimizing the source/drain contacts, high-performance GAA-FET devices have been successfully fabricated, based on these catalytic SiNW channels for the first time, yielding a high on/off current ratio of 10⁷ and a steep subthreshold swing of 66 mV dec⁻¹, closing the performance gap between the catalytic SiNW-FETs and state-of-the-art GAA-FETs fabricated by using advanced top-down EBL and EUV lithography. These results indicate that catalytic IPSLS SiNWs can also serve as the ideal 1D channels for scalable fabrication of high-performance GAA-FETs, well suited for monolithic 3D integrations.

Highlights:
1 A high-density array of orderly silicon nanowires (SiNWs) was grown in precise locations, with diameter of D_NW = 22.4 ± 2.4 nm and interwire spacing of 90 nm.
2 A special suspension-contact protocol has been developed to reliably suspend the in-plane solid-liquid-solid SiNWs to serve as ultrathin quasi-1D channels for gate-all-around field-effect transistors (GAA-FETs).
3 By optimizing the source/drain metal contacts, high-performance catalytical GAA-FETs have been successfully demonstrated, achieving a high on/off current ratio of 10⁷ and a steep subthreshold swing of 66 mV dec^-1.

Robust and High-Wettability Cellulose Separators with Molecule-Reassembled Nano-Cracked Structures for High-Performance Supercapacitors

2025-02-21T09:30:53+00:00

Separators in supercapacitors (SCs) frequently suffer from high resistance and the risk of short circuits due to inadequate electrolyte wettability, depressed mechanical properties, and insufficient thermal stability. Here, we develop a high-performance regenerated cellulose separator with nano-cracked structures for SCs via a binary solvent of superbase-derived ionic liquid and dimethylsulfoxide (DMSO). The unique nano-cracks with an average width of 7.45 nm arise from the acceleration of cellulose molecular reassembly by DMSO-regulated hydrogen bonding, which endows the separator with high porosity (70.2%) and excellent electrolyte retention (329%). The outstanding thermal stability (273 °C) and mechanical strength (70 MPa) enable the separator to maintain its structural integrity under high temperatures and external forces. With these benefits, the SC utilizing the cellulose separator enables a high specific capacitance of 93.6 F g⁻¹ at 1.0 A g⁻¹ and a remarkable capacitance retention of 99.5% after 10,000 cycles compared with the commercial NKK-MPF30AC and NKK-TF4030. The robust and high-wettability cellulose separator holds promise as a superior alternative to commercial separators for advanced SCs with enhanced performance and improved safety.

Highlights:
1 A robust and high-wettability cellulose separator with unique nano-cracked structures is constructed through hydrogen bond-driven reassembly of cellulose molecules using a green binary solvent.
2 The nano-cracked structures endow the separator with high porosity (70.2%) and excellent electrolyte retention (329%).
3 The supercapacitors with nano-cracked separators exhibit high specific capacitance (93.6 F g⁻¹ at 1.0 A g⁻¹) and a long cycling life (99.5% retention after 10,000 cycles).

Wireless, Multifunctional System-Integrated Programmable Soft Robot

2025-02-18T02:28:54+00:00

Soft robots have partially or entirely provided versatile opportunities for issues or roles that cannot be addressed by conventional machine robots, although most studies are limited to designs, controls, or physical/mechanical motions. Here, we present a transformable, reconfigurable robotic platform created by the integration of magnetically responsive soft composite matrices with deformable multifunctional electronics. Magnetic compounds engineered to undergo phase transition at a low temperature can readily achieve reversible magnetization and conduct various changes of motions and shapes. Thin and flexible electronic system designed with mechanical dynamics does not interfere with movements of the soft electronic robot, and the performances of wireless circuit, sensors, and devices are independent of a variety of activities, all of which are verified by theoretical studies. Demonstration of navigations and electronic operations in an artificial track highlights the potential of the integrated soft robot for on-demand, environments-responsive movements/metamorphoses, and optoelectrical detection and stimulation. Further improvements to a miniaturized, sophisticated system with material options enable in situ monitoring and treatment in envisioned areas such as biomedical implants.

Highlights:
1 A soft, untethered electronic robot that integrates magnetically responsive engineered composites, enabling reversible programming and a diverse range of motions and shapes.
2 Seamless integration of a meticulously designed soft/flexible electronic system with the magnetic soft robot guarantees the stable and accurate execution of multi-modal electrical functions while preserving the integrity of its mechanical movement.
3 The comprehensive demonstration illustrates the feasibility of the untethered, integrated magnetic soft robot, highlighting its stable operation, adaptability, and ability to perform complex tasks under diverse conditions.

A Transparent Polymer-Composite Film for Window Energy Conservation

2025-02-18T02:19:26+00:00

As living standards improve, the energy consumption for regulating indoor temperature keeps increasing. Windows, in particular, enhance indoor brightness but also lead to increased energy loss, especially in sunny weather. Developing a product that can maintain indoor brightness while reducing energy consumption is a challenge. We developed a facile, spectrally selective transparent ultrahigh-molecular-weight polyethylene composite film to address this trade-off. It is based on a blend of antimony-doped tin oxide and then spin-coated hydrophobic fumed silica, achieving a high visible light transmittance (> 70%) and high shielding rates for ultraviolet (> 90%) and near-infrared (> 70%). When applied to the acrylic window of containers and placed outside, this film can cause a 10 °C temperature drop compared to a pure polymer film. Moreover, in building energy simulations, the annual energy savings could be between 14.1% ~ 31.9% per year. The development of energy-efficient and eco-friendly transparent films is crucial for reducing energy consumption and promoting sustainability in the window environment.

Highlights:
1 The resultant film offers high visible light transmittance (>70%) while effectively blocking UV (>90%) and NIR (>70%) radiation, addressing the balance between natural lighting and solar energy control.
2 Incorporating hydrophobic silica, it achieves high emissivity for radiative cooling, reducing indoor temperatures by up to 10 °C and achieving maximum additional cooling energy savings of 261 MJ m⁻² per year.
3 Its superhydrophobic surface ensures excellent self-cleaning properties and durability, making it highly suitable for long-term outdoor applications.

Tailoring the Reversible Phase Transition of Perovskite Nanofiber Electrodes for High-Performance and Durable Reversible Solid Oxide Cells

2025-02-18T02:06:29+00:00

Reversible solid oxide cells (RSOCs) are capable of converting various energy resources, between electricity and chemical fuels, with high efficiency and flexibility, making them suitable for grid balancing and renewable energy consumption. However, the practical application of RSOCs is still limited by the insufficient activity and stability of the electrodes in different operating modes. Herein, a highly efficient symmetrical electrode composed of La_0.3Sr_0.6Ti_0.1Co_0.2Fe_0.7O_3−δ (LSTCF) nanofibers and in situ exsolved Co₃Fe₇ nanoparticles is developed for boosting the performance of RSOCs. The reversible phase transition, high activity and stability of the electrode have been confirmed by a combination of experimental (e.g., transmission electron microscopy and X-ray absorption fine structure) and computational studies. Electrolyte-supported RSOCs with the symmetrical electrode demonstrate excellent catalytic activity and stability, achieving a high peak power density of 0.98 W cm⁻² in the fuel cell mode using H₂ as the fuel (or 0.53 W cm⁻² using CH₄ as the fuel) and a high current density of 1.09 A cm⁻² at 1.4 V in the CO₂ electrolysis mode (or 1.03 A cm⁻² at 1.3 V for H₂O electrolysis) at 800 °C while maintaining excellent durability for over 100 h.

Highlights:
1 La_0.3Sr_0.6Ti_0.1Co_0.2Fe_0.7O₃−δ (LSTCF) nanofibers showed high structural reversibility.
2 LSTCF fibers and CoFe nanoparticles were reconstructed through a reversible phase transition process.
3 The LSTCF fiber electrode demonstrated excellent activity and stability for power and fuel co-generation.

Absorption–Reflection–Transmission Power Coefficient Guiding Gradient Distribution of Magnetic MXene in Layered Composites for Electromagnetic Wave Absorption

2025-02-18T01:12:57+00:00

The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties, but it is often ignored. Herein, a comprehensive consideration including electromagnetic component regulation, layered arrangement structure, and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss. On the microscale, the incorporation of magnetic Ni nanoparticles into MXene nanosheets (Ni@MXene) endows suitable intrinsic permittivity and permeability. On the macroscale, the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves, inducing multiple reflection/scattering effects. On this basis, according to the analysis of absorption, reflection, and transmission (A–R–T) power coefficients of layered composites, the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer, electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer. Consequently, the layered gradient composite (LG5-10–15) achieves complete absorption coverage of X-band at thickness of 2.00–2.20 mm with RL_min of −68.67 dB at 9.85 GHz in 2.05 mm, which is 199.0%, 12.6%, and 50.6% higher than non-layered, layered and layered descending gradient composites, respectively. Therefore, this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.

Highlights:
1 The layered arrangement and gradient distribution of magnetic MXene are firstly combined to improve the electromagnetic wave (EMW) RLmin and broaden effective absorption bandwidth.
2 Absorption, reflection, and transmission (A–R–T) power coefficient analysis is firstly used to guide the gradient distribution, so as to realize EMW incidence at low-concentration surface, loss at middle concentration interlayer and reflection at high-concentration bottom.
3 The layered gradient composite (LG5-10-15) achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RLmin of -68.67 dB.

Understanding the Decoupled Effects of Cations and Anions Doping for High-Performance Perovskite Solar Cells

2025-02-15T04:08:37+00:00

The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells (PSCs). However, serious ion migration hampers their operational stability. Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration, the impact of cations or anions is not individually explored, which hinders the evaluation of different cations and further application of doping strategy. Here we report that a special group of sulfonic anions (like CF₃SO₃⁻) successfully introduce alkaline earth ions (like Ca²⁺) into perovskite lattice compared to its halide counterparts. Furthermore, with effective crystallization regulation and defect passivation of sulfonic anions, perovskite with Ca(CF₃SO₃)₂ shows reduced PbI₂ residue and metallic Pb⁰ defects; thereby, corresponding PSCs show an enhanced PCE of 24.95%. Finally by comparing the properties of perovskite with Ca(CF₃SO₃)₂ and FACF₃SO₃, we found that doped Ca²⁺ significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF₃SO₃)₂-doped PSCs, while no obvious impact of Ca²⁺on trap density is observed. Combining the benefits of cations and anions, this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.

Highlights:
1 Alkaline earth cations are successfully incorporated into perovskite lattice with the aid of sulfonic acid anions, while alkaline earth metal halides are lack of doping capacity.
2 The sulfonic acid anions effectively regulate the crystallization of perovskite and passivate the metallic Pb0 defect states, thereby improving the power conversion efficiency of perovskite solar cells.
3 By comparing the property of FACF₃SO₃ and Ca(CF₃SO₃)₂-doped perovskite films, the impact of suppressing halide migration with an activation energy of 1.246 eV is attributed to Ca²⁺ cations, thus providing methodology for decoupling the effects of cations and anions.

Thin and Flexible Breeze-Sense Generators for Non-Contact Haptic Feedback in Virtual Reality

2025-02-15T03:55:30+00:00

In the realm of virtual reality (VR), haptic feedback is integral to enhance the immersive experience; yet, existing wearable devices predominantly rely on skin contact feedback, lacking options for compact and non-contact breeze-sense feedback. Herein, we propose a compact and non-contact working model piezoelectret actuator for providing a gentle and safe breeze sensation. This easy-fabricated and flexible breeze-sense generator with thickness around 1 mm generates air flow pressure up to ~ 163 Pa, which is significantly sensed by human skin. In a typical demonstration, the breeze-sense generators array showcases its versatility by employing multiple coded modes for non-contact information transmitting. The thin thinness and good flexibility facilitate seamless integration with wearable VR setups, and the wearable arrays empower volunteers to precisely perceive the continuous and sudden breeze senses in the virtual environments. This work is expected to inspire developing new haptic feedback devices that play pivotal roles in human–machine interfaces for VR applications.

Highlights:
1 The breeze-sense generators generate significant air flow pressure output of ~ 163 Pa that can easily be sensed by human skin and have an overall thickness around 1 mm.
2 Volunteers successfully identify multiple programming patterns transmitted by the generators array.
3 A wearable breeze-sense feedback system effectively provides the continuous or sudden breeze senses in virtual reality environments.

Integrating Electric Ambipolar Effect for High-Performance Zinc Bromide Batteries

2025-02-15T03:42:12+00:00

The coupling of fast redox kinetics, high-energy density, and prolonged lifespan is a permanent aspiration for aqueous rechargeable zinc batteries, but which has been severely hampered by a narrow voltage range and suboptimal compatibility between the electrolytes and electrodes. Here, we unprecedentedly introduced an electric ambipolar effect for synergistic manipulation on Zn²⁺ ternary-hydrated eutectic electrolyte (ZTE) enabling high-performance Zn-Br₂ batteries. The electric ambipolar effect motivates strong dipole interactions among hydrated perchlorates and bipolar ligands of L-carnitine (L-CN) and sulfamide, which reorganized primary cations solvation sheath in a manner of forming Zn[(L-CN)(SA)(H₂O)₄]²⁺ configuration and dynamically restricting desolvated H₂O molecules, thus ensuring a broadened electrochemical window of 2.9 V coupled with high ionic conductivity. Noticeably, L-CN affords an electrostatic shielding effect and an in situ construction of organic–inorganic interphase, endowing oriented Zn anode plating/stripping reversibly for over 2400 h. Therefore, with the synergy of electro/nucleophilicity and exceptional compatibility, the ZTE electrolyte dynamically boosts the conversion redox of Zn-Br₂ batteries in terms of high specific capacity and stable cycling performance. These findings open a window for designing electrolytes with synergetic chemical stability and compatibility toward advanced zinc-ion batteries.

Highlights:
1 Electric ambipolar effect motivates strong dipole interactions reorganized primary cations solvation sheath.
2 Electrostatic shielding homogenized the distribution for nucleated Zn and facilized the orientated Zn deposition.
3 The eutectic network of Zn²⁺ ternary hydrated eutectic electrolytes enables highly reversible and noteworthy Br₂/Br⁻ reaction kinetics.

Synergistic Single-Atom and Clustered Cobalt Sites on N/S Co-Doped Defect Nano-Carbon for Efficient H2O2 Electrosynthesis

2025-02-15T03:30:02+00:00

Non-noble-based single atomic catalysts have exhibited significant potential in electrochemical production of H₂O₂ via two-electron oxygen reduction reactions (2e⁻ ORR). However, constructing highly efficient and acid-resistant catalysts remains a challenge but significant. In this work, fullerene (C₆₀) with abundant pentagonal inherent defects was employed as a carbon substrate to synthesize defect-rich nanocarbon electrocatalysts doped with NSCo single atoms and accompanied by metallic Co nanoparticles (CoSA/CoNP-NSDNC) for the first time. The electrochemical experiments demonstrate that the active sites of CoSA/CoNP-NSDNC are formed through the synergistic interaction between NSCo single atoms and Co nanoparticle clusters embedded within the carbon framework. The obtained CoSA/CoNP-NSDNC catalyst exhibits an onset potential as 0.72 V versus RHE and achieves up to 90% H₂O₂ selectivity over a wide potential range of 500 mV. Moreover, the as-obtained CoSA/CoNP-NSDNC configured as the cathode in a self-assembled flow cell under acidic conditions achieves a high H₂O₂ production rate of 4206.96 mmol g_cat⁻¹ h⁻¹ with a Faraday efficiency of ∼ 95% and exhibit ultra fast degradation of organic pollutants. This work focuses on the synergistic effect of non-noble metal nanoparticles, metal single-atom sites, and topological defects on the 2e⁻ ORR process, which provides a new direction for designing carbon-based catalysts for efficient H₂O₂ electrosynthesis.

Highlights:
1 Defect-rich nanocarbon catalyst (CoSA/CoNP-NSDNC) synthesized using NSCo single atoms and Co nanoparticle clusters on fullerene-derived carbon framework, enabling efficient H₂O₂ electrosynthesis.
2 The CoSA/CoNP-NSDNC catalyst exhibits high H₂O₂ selectivity (~ 90%) over a wide potential range with an onset potential of 0.72 V versus RHE, achieving Faraday efficiency close to 95% in acidic conditions.
3 Demonstrates potential for environmental applications, achieving high H₂O₂ production (4206.96 mmol g⁻¹ h⁻¹) in a flow cell setup, along with efficient degradation of organic pollutants in Fenton-like reactions.

Top-Down Dual-Interface Carrier Management for Highly Efficient and Stable Perovskite/Silicon Tandem Solar Cells

2025-02-15T03:15:19+00:00

Despite significant advancements in the power conversion efficiency (PCE) of perovskite/silicon tandem solar cells, improving carrier management in top cells remains challenging due to the defective dual interfaces of wide-bandgap perovskite, particularly on textured silicon surfaces. Herein, a series of halide ions (Cl⁻, Br⁻, I⁻) substituted piperazinium salts are designed and synthesized as post-treatment modifiers for perovskite surfaces. Notably, piperazinium chloride induces an asymmetric bidirectional ions distribution from the top to the bottom surface, with large piperazinium cations concentrating at the perovskite surface and small chloride anions migrating downward to accumulate at the buried interface. This results in effective dual-interface defect passivation and energy band modulation, enabling wide-bandgap (1.68 eV) perovskite solar cells to achieve a PCE of 22.3% and a record product of open-circuit voltage × fill factor (84.4% relative to the Shockley–Queisser limit). Furthermore, the device retains 91.3% of its initial efficiency after 1200 h of maximum power point tracking without encapsulation. When integrated with double-textured silicon heterojunction solar cells, a remarkable PCE of 31.5% is achieved for a 1.04 cm² monolithic perovskite/silicon tandem solar cell, exhibiting excellent long-term operational stability (T₈₀ = 755 h) without encapsulation in ambient air. This work provides a convenient strategy on dual-interface engineering for making high-efficiency and stable perovskite platforms.

Highlights:
1 An innovated top-down dual-interface carrier management strategy is developed to effectively improve both interfaces of the wide-bandgap perovskite using a multi-functionalized piperazinium chloride post-treatment.
2 The 1.68 eV unencapsulated single-junction perovskite solar cells exhibit a champion PCE of 22.3%, with a record VOC × FF product (84.4% relative to the Shockley–Queisser limit).
3 An impressive PCE of 31.5% for the 1.04 cm² monolithic perovskite/silicon tandem solar cell based on silicon heterojunction bottom cell is demonstrated.

Construction of Multifunctional Conductive Carbon-Based Cathode Additives for Boosting Li6PS5Cl-Based All-Solid-State Lithium Batteries

2025-02-15T03:02:29+00:00

The electrochemical performance of all-solid-state lithium batteries (ASSLBs) can be prominently enhanced by minimizing the detrimental degradation of solid electrolytes through their undesirable side reactions with the conductive carbon additives (CCAs) inside the composite cathodes. Herein, the well-defined Mo₃Ni₃N nanosheets embedded onto the N-doped porous carbons (NPCs) substrate are successfully synthesized (Mo-Ni@NPCs) as CCAs inside LiCoO₂ for Li₆PSC₅Cl (LPSCl)-based ASSLBs. This nano-composite not only makes it difficult for hydroxide groups (–OH) to survive on the surface but also allows the in situ surface reconstruction to generate the ultra-stable MoS₂-Mo₃Ni₃N heterostructures after the initial cycling stage. These can effectively prevent the occurrence of OH-induced LPSC decomposition reaction from producing harmful insulating sulfates, as well as simultaneously constructing the highly-efficient electrons/ions dual-migration pathways at the cathode interfaces to facilitate the improvement of both electrons and Li⁺ ions conductivities in ASSLBs. With this approach, fine-tuned Mo-Ni@NPCs can deliver extremely outstanding performance, including an ultra-high first discharge-specific capacity of 148.61 mAh g⁻¹ (0.1C), a high Coulombic efficiency (94.01%), and a capacity retention rate after 1000 cycles still attain as high as 90.62%. This work provides a brand-new approach of “conversion-protection” strategy to overcome the drawbacks of composite cathodes interfaces instability and further promotes the commercialization of ASSLBs.

Highlights:
1 This work provides a brand-new approach to the “conversion-protection” strategy to overcome the drawbacks of composite cathode interfaces.
2 The Mo₃Ni₃N not only makes it difficult for hydroxide groups (-OH) to survive on the surface but also allows the in situ surface reconstruction to generate the ultra-stable MoS₂-Mo₃Ni₃N heterostructures after the initial cycling stage.
3 The Mo-Ni@NPCs/LCO/LPSC-based ASSLBs achieve high-capacity retention (90.62%) and excellent cycle life (1000 cycles).

Highly Thermally Conductive and Flame-Retardant Waterborne Polyurethane Composites with 3D BNNS Bridging Structures via Magnetic Field Assistance

2025-02-11T04:38:14+00:00

The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices. Hence, a composite with three-dimensional network (Ho/U-BNNS/WPU) is developed by simultaneously incorporating magnetically modified boron nitride nanosheets (M@BNNS) and non-magnetic organo-grafted BNNS (U-BNNS) into waterborne polyurethane (WPU) to synchronous molding under a horizontal magnetic field. The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction, combined with the bridging structure established by U-BNNS, enable Ho/U-BNNS/WPU to exhibit exceptional in-plane (λ_//) and through-plane thermal conductivities (λ_⊥). In particular, with the addition of 30 wt% M@BNNS and 5 wt% U-BNNS, the λ_// and λ_⊥ of composites reach 11.47 and 2.88 W m⁻¹ K⁻¹, respectively, which representing a 194.2% improvement in λ_⊥ compared to the composites with a single orientation of M@BNNS. Meanwhile, Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips. The composites also demonstrate excellent flame retardancy, with a peak heat release and total heat release reduced by 58.9% and 36.9%, respectively, compared to WPU. Thus, this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites, presenting broad application potential in electronic packaging fields.

Highlights:
1 By simultaneously incorporating the magnetic filler-modified boron nitride nanosheets (M@BNNS) and the non-magnetic filler U-BNNS into the polymer matrix, a three-dimensional heat conduction pathway composites are obtained under a horizontal magnetic field.
2 Owing to the microstructural design of the 3D-bridging architecture, with the addition of only 5 wt% U-BNNS, the λ⊥ of composites achieved 2.88 W m⁻¹ K⁻¹, representing a remarkable increase of 194.2% compared to single-oriented composites.
3 The 3D-bridging architecture composite also demonstrates excellent flame retardancy, attributed to the synergistic mechanisms of condensed and gas phases, effectively mitigating the risks of thermal runaway in electronic devices.

Electromagnetic Functions Modulation of Recycled By-Products by Heterodimensional Structure

2025-02-11T04:27:00+00:00

One of the significant technological challenges in safeguarding electronic devices pertains to the modulation of electromagnetic (EM) wave jamming and the recycling of defensive shields. The synergistic effect of heterodimensional materials can effectively enable the manipulation of EM waves by altering the nanostructure. Here we propose a novel approach for upcycling by-products of silver nanowires that can fabricate shape-tunable aerogels which enable the modulation of its interaction with microwaves by heterodimensional structure of by-products. By-product heterodimensionality was used to design EM-wave-jamming-dissipation structures and therefore two typical tunable aerogel forms were studied. The first tunable form was aerogel film, which shielded EM interference (EMI shielding effectiveness (EMI SE) > 89 dB) and the second tunable form was foam, which performed dual EM functions (SE > 30 dB& reflective loss (RL) < -35 dB, effective absorption bandwidth (EAB) > 6.7 GHz). We show that secondary recycled aerogels retain nearly all of their EM protection properties, making this type of closed-loop cycle an appealing option. Our findings pave the way for the development of adaptive EM functions with nanoscale regulation in a green and closed-loop cycle, and they shed light on the fundamental understanding of microwave interactions with heterodimensional structures.

Highlights:
1 Turning trash into treasure: The outstanding tunable aerogels were fabricated via heterodimensional by-products of silver nanowires. The first tunable form, aerogel film, shields electromagnetic interference (EMI SE > 89 dB), while the second tunable form, aerogel foam, performs dual EM functions (EMI SE > 30 dB and RL < -35 dB, EAB > 6.7 GHz).
2 Recycle again: The secondary recycled aerogels retain nearly all of their EM protection qualities, making this closed-loop cycle desirable.

Multifunctional Janus-Structured Polytetrafluoroethylene-Carbon Nanotube-Fe3O4/MXene Membranes for Enhanced EMI Shielding and Thermal Management

2025-02-11T04:17:06+00:00

Herein, a novel Janus-structured multifunctional membrane with integrated electromagnetic interference (EMI) shielding and personalized thermal management is fabricated using shear-induced in situ fibrillation and vacuum-assisted filtration. Interestingly, within the polytetrafluoroethylene (PTFE)-carbon nanotube (CNT)-Fe₃O₄ layer (FCFe), CNT nanofibers interweave with PTFE fibers to form a stable “silk-like” structure that effectively captures Fe₃O₄ particles. By incorporating a highly conductive MXene layer, the FCFe/MXene (FCFe/M) membrane exhibits excellent electrical/thermal conductivity, mechanical properties, and flame retardancy. Impressively, benefiting from the rational regulation of component proportions and the design of a Janus structure, the FCFe/M membrane with a thickness of only 84.9 µm delivers outstanding EMI shielding effectiveness of 44.56 dB in the X-band, with a normalized specific SE reaching 10,421.3 dB cm² g⁻¹, which is attributed to the “absorption-reflection-reabsorption” mechanism. Furthermore, the membrane demonstrates low-voltage-driven Joule heating and fast-response photothermal performance. Under the stimulation of a 3 V voltage and an optical power density of 320 mW cm⁻², the surface temperatures of the FCFe/M membranes can reach up to 140.4 and 145.7 °C, respectively. In brief, the FCFe/M membrane with anti-electromagnetic radiation and temperature regulation is an attractive candidate for the next generation of wearable electronics, EMI compatibility, visual heating, thermotherapy, and military and aerospace applications.

Highlights:
1 The Janus-type multifunctional ultra-flexible polytetrafluoroethylene-carbon nanotube-Fe₃O₄/MXene (FCFe/M) membranes were fabricated via a shear-induced in situ fibrillation technique followed by vacuum-assisted filtration.
2 Thanks to the strategic distribution of the MXene conductive reflection layer and the silk-like FCFe electromagnetic wave’s absorption layer, the membranes achieve robust electromagnetic interference shielding and effective antireflection through the absorption-reflection-reabsorption mechanism.
3 The membranes exhibit exceptional thermal management performance, including efficient heat dissipation and electrothermal/photothermal conversion capabilities, further enhancing their promising potential for applications in flexible wearable technologies.

Functionalized Aluminum Nitride for Improving Hydrolysis Resistances of Highly Thermally Conductive Polysiloxane Composites

2025-02-11T03:51:00+00:00

A series of divinylphenyl-acryloyl chloride copolymers (PDVB-co-PACl) is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers. PDVB-co-PACl is utilized to graft on the surface of spherical aluminum nitride (AlN) to prepare functionalized AlN (AlN@PDVB-co-PACl). Polymethylhydrosiloxane (PMHS) is then used as the matrix to prepare thermally conductive AlN@PDVB-co-PACl/PMHS composites with AlN@PDVB-co-PACl as fillers through blending and curing. The grafting of PDVB-co-PACl synchronously enhances the hydrolysis resistance of AlN and its interfacial compatibility with PMHS matrix. When the molecular weight of PDVB-co-PACl is 5100 g mol⁻¹ and the grafting density is 0.8 wt%, the composites containing 75 wt% of AlN@PDVB-co-PACl exhibit the optimal comprehensive performance. The thermal conductivity (λ) of the composite is 1.14 W m⁻¹ K⁻¹, which enhances by 20% and 420% compared to the λ of simply physically blended AlN/PMHS composite and pure PMHS, respectively. Meanwhile, AlN@PDVB-co-PACl/PMHS composites display remarkable hydrothermal aging resistance by retaining 99.1% of its λ after soaking in 90 °C deionized water for 80 h, whereas the λ of the blended AlN/PMHS composites decreases sharply to 93.7%.

Highlights:
1 Copolymer of divinylphenyl-acryloyl chloride copolymers (PDVB-co-PACl) is designed and synthesized to graft on the surface of aluminum nitride (AlN) to improve its hydrolysis resistance.
2 AlN fillers functionalized by PDVB-co-PACl with the molecular weight of 5100 g mol^-1 exhibits the highest hydrolysis resistance and the lowest interfacial thermal resistance.
3 When the mass fraction of AlN@PDVB-co-PACl is 75 wt% and the grafting density of PDVB-co-PACl is 0.8 wt%, the λ for AlN@PDVB-co-PACl/PMHS composites is 1.14 W m^-1 K^-1 and maintains 99.1% after soaking in 90 °C deionized water for 80 h.

Multifunctional Carbon Foam with Nanoscale Chiral Magnetic Heterostructures for Broadband Microwave Absorption in Low Frequency

2025-02-11T03:41:20+00:00

The construction of carbon nanocoil (CNC)-based chiral-dielectric-magnetic trinity composites is considered as a promising approach to achieve excellent low-frequency microwave absorption. However, it is still challenging to further enhance the low frequency microwave absorption and elucidate the related loss mechanisms. Herein, the chiral CNCs are first synthesized on a three-dimensional (3D) carbon foam and then combined with the FeNi/NiFe₂O₄ nanoparticles to form a novel chiral-dielectric-magnetic trinity foam. The 3D porous CNC-carbon foam network provides excellent impedance matching and strong conduction loss. The formation of the FeNi-carbon interfaces induces interfacial polarization loss, which is confirmed by the density functional theory calculations. Further permeability analysis and the micromagnetic simulation indicate that the nanoscale chiral magnetic heterostructures achieve magnetic pinning and coupling effects, which enhance the magnetic anisotropy and magnetic loss capability. Owing to the synergistic effect between dielectricity, chirality, and magnetism, the trinity composite foam exhibits excellent microwave absorption performance with an ultrabroad effective absorption bandwidth (EAB) of 14 GHz and a minimum reflection of loss less than − 50 dB. More importantly, the C-band EAB of the foam is extended to 4 GHz, achieving the full C-band coverage. This study provides further guidelines for the microstructure design of the chiral-dielectric-magnetic trinity composites to achieve broadband microwave absorption.

Highlights:
1 A novel multifunctional carbon foam with nanoscale chiral magnetic heterostructures is constructed, in which the interconnection network provides strong conduction loss.
2 The interfacial polarization loss induced by the FeNi-carbon interfaces is confirmed by the density functional theory calculations, and the magnetic pinning and coupling effects are revealed by the micromagnetic simulation.
3 The composite foam exhibits an ultrabroad effective absorption bandwidth (EAB) of 14 GHz and a C-band EAB of 4 GHz, achieving the full C-band coverage.

Light Management in 2D Perovskite Toward High-Performance Optoelectronic Applications

2025-02-09T05:01:40+00:00

Two-dimensional Dion-Jacobson (DJ) perovskite has garnered significant attention due to its superior responsivity and operation stability. However, efforts are predominantly focused on discovering new organic spacer to synthesize novel perovskites, while material-form-associated light management, which is crucial for enhancing the photodetector’s efficiency, is largely overlooked. Herein, we introduced surface light management strategy into DJ-type perovskite system by synthesizing surface-patterned BDAPbBr₄ (BPB, BDA = NH₃(CH₂)₄NH₃) microplates (MPs) using template-assisted space-confined method, which was further elucidated by theoretical optical simulation. By leveraging surface-patterned MPs to enhance light absorption, the BPB-based photodetectors (PDs) achieved remarkable photoresponse in ultraviolet region, marked by a high on/off ratio (~ 5000), superior responsivity (2.24 A W⁻¹), along with large detectivity (~ 10¹³ Jones) and low detection limit (68.7 nW cm⁻²). Additionally, the PDs showcased superior light communication and imaging capabilities even under weak-light illumination. Notably, the anisotropic nature of the surface-patterned MPs conferred excellent polarization sensitivity to the PD. These results represented the first demonstration of BPB perovskite in weak-light communication and imaging, as well as in polarized light detection. Our findings offer valuable insights into enhancing photodetector performance and optoelectronic applications through surface light management strategies.

Highlights:
1 The light management strategy is introduced into two-dimensional Dion-Jacobson (2D DJ) perovskite and subsequently elucidated both experimentally and theoretically.
2 The synthesis of surface-patterned BDAPbBr₄ microplates with high crystalline quality demonstrates the first reported instance of growing such 2D DJ-type perovskite microplates.
3 The optimized device exhibits excellent photodetection performance under UV region. Moreover, this work represents the successful demonstration of BDAPbBr₄ perovskite for UV weak-light communication, imaging, and polarized light detection.

Enhanced Conductivity of Multilayer Copper–Carbon Nanofilms via Plasma Immersion Deposition

2025-02-09T04:52:25+00:00

Although room-temperature superconductivity is still difficult to achieve, researching materials with electrical conductivity significantly higher than that of copper will be of great importance in improving energy efficiency, reducing costs, lightening equipment weight, and enhancing overall performance. Herein, this study presents a novel copper–carbon nanofilm composite with enhanced conductivity which has great applications in the electronic devices and electrical equipment. Multilayer copper–carbon nanofilms and interfaces with superior electronic structures are formed based on copper materials using plasma immersion nanocarbon layer deposition technology, effectively enhancing conductivity. Experimental results show that for a five-layer copper–carbon nanofilm composite, the conductivity improves significantly when the thickness of the carbon nanofilm increases. When the carbon nanofilm accounts for 16% of the total thickness, the overall conductivity increases up to 30.20% compared to pure copper. The mechanism of the enhanced conductivity is analyzed including roles of copper atom adsorption sites and electron migration pathways by applying effective medium theory, first-principles calculations and density of states analysis. Under an applied electric field, the high-density electrons in the copper film can migrate into the nanocarbon film, forming highly efficient electron transport channels, which significantly enhance the material’s conductivity. Finally, large-area electrode coating equipment is developed based on this study, providing the novel and robust strategy to enhance the conductivity of copper materials, which enables industrial application of copper–carbon nanocomposite films in the field of high conductivity materials.

Highlights:
1 With plasma immersion deposition technology, multilayer copper–carbon nanofilms were fabricated and conductivity can achieve up to 30.20% increase compared to pure copper.
2 By applying effective medium theory, first-principles calculations, and density of states analysis, the critical roles of copper atom adsorption sites and electron migration pathways within the nanocarbon film were analyzed, elucidating the mechanism of the conductivity enhancement.
3 Large-scale electrode coating equipment suitable for industrial production was developed.

Multiscale Biomimetic Evaporators Based on Liquid Metal/Polyacrylonitrile Composite Fibers for Highly Efficient Solar Steam Generation

2025-02-09T04:43:30+00:00

Solar steam generation (SSG) offers a cost-effective solution for producing clean water by utilizing solar energy. However, integrating effective thermal management and water transportation to develop high-efficiency solar evaporators remains a significant challenge. Here, inspired by the hierarchical structure of the stem of bird of paradise, a three-dimensional multiscale liquid metal/polyacrylonitrile (LM/PAN) evaporator is fabricated by assembling LM/PAN fibers. The strong localized surface plasmon resonance of LM particles and porous structure of LM/PAN fibers with interconnected channels lead to efficient light absorption up to 90.9%. Consequently, the multiscale biomimetic LM/PAN evaporator achieves an outstanding water evaporation rate of 2.66 kg m⁻² h⁻¹ with a solar energy efficiency of 96.5% under one sun irradiation and an exceptional water rate of 2.58 kg m⁻² h⁻¹ in brine. Additionally, the LM/PAN evaporator demonstrates a superior purification performance for seawater, with the concentration of Na⁺, Mg²⁺, K⁺ and Ca²⁺ in real seawater dramatically decreased by three orders to less than 7 mg L⁻¹ after desalination under light irradiation. The multiscale LM/PAN evaporator with hierarchical structure regulates the water transportation as well as thermal management for highly effective solar-driven evaporation, providing valuable insight into the structural design principles for advanced SSG systems.

Highlights:
1 A three-dimensional multiscale liquid metal/polyacrylonitrile evaporator is fabricated through wet spinning and assembly.
2 The evaporator exhibits an outstanding water evaporation rate of 2.66 kg m⁻² h⁻¹ with a solar energy efficiency of 96.5% under one sun irradiation.
3 The evaporator demonstrates a superior purification performance for seawater and sewage under light irradiation.

Laser-Induced Nanowire Percolation Interlocking for Ultrarobust Soft Electronics

2025-02-07T07:10:04+00:00

Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties. However, weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability, necessitating the use of an insulating protective layer, which greatly limits their utility. Herein, we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer. In this method, the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix, resulting in mechanical interlocking through percolation. This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates, significantly enhancing its universality in diverse applications. Thereby, we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor. Furthermore, enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment, broadening its application into various electrochemical devices.

Highlights:
1 Laser-induced percolation interlocking technology enables the development of the robust, open-structured nanowire (NW) electrodes through the photothermal effect at the interface between NW and substrate.
2 The optimized NW electrode with enhanced mechanical and electrical properties can be used as reusable wearable electronics.
3 Stable functionalization of the percolation-interlocked NW electrode with various conducting polymers can be achieved, broadening the applicability as soft electronics.

Atomically Dispersed Metal Atoms: Minimizing Interfacial Charge Transport Barrier for Efficient Carbon-Based Perovskite Solar Cells

2025-02-07T06:46:43+00:00

Carbon-based perovskite solar cells (C-PSCs) exhibit notable stability and durability. However, the power conversion efficiency (PCE) is significantly hindered by energy level mismatches, which result in interfacial charge transport barriers at the electrode-related interfaces. Herein, we report a back electrode that utilizes atomically dispersed metallic cobalt (Co) in carbon nanosheets (Co₁/CN) to adjust the interfacial energy levels. The electrons in the d-orbitals of Co atoms disrupt the electronic symmetry of the carbon nanosheets (CN), inducing a redistribution of the electronic density of states that leads to a downward shift in the Fermi level and a significantly reduced interfacial energy barrier. As a result, the C-PSCs using Co₁/CN as back electrodes achieve a notable PCE of 22.61% with exceptional long-term stability, maintaining 94.4% of their initial efficiency after 1000 h of continuous illumination without encapsulation. This work provides a promising universal method to regulate the energy level of carbon electrodes for C-PSCs and paves the way for more efficient, stable, and scalable solar technologies toward commercialization.

Highlights:
1 Atomically dispersed metal atoms effectively enhance energy level alignment and reduce energy losses at the electrode interfaces.
2 The optimized carbon-based perovskite solar cells achieve a power conversion efficiency (PCE) of 22.61% and maintain 94.4% of their initial PCE after 1000 h under continuous illumination without encapsulation.

Transition Metal Carbonitride MXenes Anchored with Pt Sub-Nanometer Clusters to Achieve High-Performance Hydrogen Evolution Reaction at All pH Range

2025-02-07T05:53:31+00:00

Transition metal carbides, known as MXenes, particularly Ti₃C₂T_x, have been extensively explored as promising materials for electrochemical reactions. However, transition metal carbonitride MXenes with high nitrogen content for electrochemical reactions are rarely reported. In this work, transition metal carbonitride MXenes incorporated with Pt-based electrocatalysts, ranging from single atoms to sub-nanometer dimensions, are explored for hydrogen evolution reaction (HER). The fabricated Pt clusters/MXene catalyst exhibits superior HER performance compared to the single-atom-incorporated MXene and commercial Pt/C catalyst in both acidic and alkaline electrolytes. The optimized sample shows low overpotentials of 28, 65, and 154 mV at a current densities of 10, 100, and 500 mA cm⁻², a small Tafel slope of 29 mV dec⁻¹, a high mass activity of 1203 mA mg_Pt⁻¹ and an excellent turnover frequency of 6.1 s⁻¹ in the acidic electrolyte. Density functional theory calculations indicate that this high performance can be attributed to the enhanced active sites, increased surface functional groups, faster charge transfer dynamics, and stronger electronic interaction between Pt and MXene, resulting in optimized hydrogen absorption/desorption toward better HER. This work demonstrates that MXenes with a high content of nitrogen may be promising candidates for various catalytic reactions by incorporating single atoms or clusters.

Highlights:
1 Two-dimensional mono- and few-layered Ti₃CNT_x MXene nanosheets with extremely high nitrogen content were synthesized.
2 Better performance for hydrogen evolution reaction (HER) than Pt/C catalyst in acidic, neutral and alkaline solutions.
3 Exceptional performance of HER in both acidic and alkaline solutions.
4 A large current density (> 500 mA cm⁻²) has been achieved for HER.

Novel Cellulosic Fiber Composites with Integrated Multi-Band Electromagnetic Interference Shielding and Energy Storage Functionalities

2025-02-05T05:46:13+00:00

In an era where technological advancement and sustainability converge, developing renewable materials with multifunctional integration is increasingly in demand. This study filled a crucial gap by integrating energy storage, multi-band electromagnetic interference (EMI) shielding, and structural design into bio-based materials. Specifically, conductive polymer layers were formed within the 2,2,6,6-tetramethylpiperidine-1-oxide (TEMPO)-oxidized cellulose fiber skeleton, where a mild TEMPO-mediated oxidation system was applied to endow it with abundant macropores that could be utilized as active sites (specific surface area of 105.6 m² g⁻¹). Benefiting from the special hierarchical porous structure of the material, the constructed cellulose fiber-derived composites can realize high areal-specific capacitance of 12.44 F cm⁻² at 5 mA cm⁻² and areal energy density of 3.99 mWh cm⁻² (2005 mW cm⁻²) with an excellent stability of maintaining 90.23% after 10,000 cycles at 50 mA cm⁻². Meanwhile, the composites showed a high electrical conductivity of 877.19 S m⁻¹ and excellent EMI efficiency (> 99.99%) in multiple wavelength bands. The composite material’s EMI values exceed 100 dB across the L, S, C, and X bands, effectively shielding electromagnetic waves in daily life. The proposed strategy paves the way for utilizing bio-based materials in applications like energy storage and EMI shielding, contributing to a more sustainable future.

Highlights:
1 A mild 2,2,6,6-tetramethylpiperidine-1-oxide mediated modification system was applied to improve the reactivity and introduce porous structure of cellulose fiber skeleton.
2 Composite exhibited highly efficient electromagnetic shielding interference performance (> 99.99%) over multi-band.
3 Integrating energy storage, electromagnetic interference shielding, and structural design into bio-based materials.

Multifunctional Graphdiyne Enables Efficient Perovskite Solar Cells via Anti-Solvent Additive Engineering

2025-02-05T05:36:31+00:00

Finding ways to produce dense and smooth perovskite films with negligible defects is vital for achieving high-efficiency perovskite solar cells (PSCs). Herein, we aim to enhance the quality of the perovskite films through the utilization of a multifunctional additive in the perovskite anti-solvent, a strategy referred to as anti-solvent additive engineering. Specifically, we introduce ortho-substituted-4′-(4,4″-di-tert-butyl-1,1′:3′,1″-terphenyl)-graphdiyne (o-TB-GDY) as an AAE additive, characterized by its sp/sp²-cohybridized and highly π-conjugated structure, into the anti-solvent. o-TB-GDY not only significantly passivates undercoordinated lead defects (through potent coordination originating from specific high π–electron conjugation), but also serves as nucleation seeds to effectively enhance the nucleation and growth of perovskite crystals. This markedly reduces defects and non-radiative recombination, thereby increasing the power conversion efficiency (PCE) to 25.62% (certified as 25.01%). Meanwhile, the PSCs exhibit largely enhanced stability, maintaining 92.6% of their initial PCEs after 500 h continuous 1-sun illumination at ~ 23 °C in a nitrogen-filled glove box.

Highlights:
1 The use of novel nanographdiyne (o-TB-GDY) via anti-solvent additive engineering significantly enhances the nucleation and growth of perovskite crystals, leading to improved film quality, reduced film defects and suppressed non-radiative recombination.
2 o-TB-GDY primarily remains on the surface of the perovskite films after crystallization, where it strongly interacts with the undercoordinated Pb defects for effective passivation.
3 The optimized perovskite solar cells achieve a champion power conversion efficiency of 25.62% (certified as 25.01%) with good stability.

Zn(TFSI)2-Mediated Ring-Opening Polymerization for Electrolyte Engineering Toward Stable Aqueous Zinc Metal Batteries

2025-02-05T05:26:56+00:00

Practical Zn metal batteries have been hindered by several challenges, including Zn dendrite growth, undesirable side reactions, and unstable electrode/electrolyte interface. These issues are particularly more serious in low-concentration electrolytes. Herein, we design a Zn salt-mediated electrolyte with in situ ring-opening polymerization of the small molecule organic solvent. The Zn(TFSI)₂ salt catalyzes the ring-opening polymerization of (1,3-dioxolane (DOL)), generating oxidation-resistant and non-combustible long-chain polymer (poly(1,3-dioxolane) (pDOL)). The pDOL reduces the active H₂O molecules in electrolyte and assists in forming stable organic–inorganic gradient solid electrolyte interphase with rich organic constituents, ZnO and ZnF₂. The introduction of pDOL endows the electrolyte with several advantages: excellent Zn dendrite inhibition, improved corrosion resistance, widened electrochemical window (2.6 V), and enhanced low-temperature performance (freezing point = − 34.9 °C). Zn plating/stripping in pDOL-enhanced electrolyte lasts for 4200 cycles at 99.02% Coulomb efficiency and maintains a lifetime of 8200 h. Moreover, Zn metal anodes deliver stable cycling for 2500 h with a high Zn utilization of 60%. A Zn//VO₂ pouch cell assembled with lean electrolyte (electrolyte/capacity (E/C = 41 mL (Ah)⁻¹) also demonstrates a capacity retention ratio of 92% after 600 cycles. These results highlight the promising application prospects of practical Zn metal batteries enabled by the Zn(TFSI)₂-mediated electrolyte engineering.

Highlights:
1 A novel electrolyte enabled by Zn(TFSI)₂-mediated ring-opening polymerization strategy for highly reversible aqueous zinc metal batteries was proposed.
2 The novel electrolyte has good antioxidant stability and non-inflammability.
3 The novel electrolyte widens the electrochemical window, improves the low-temperature performance, and inhibits Zn dendrite. The Zn metal anode shows an 8200 h lifespan at 1 mAh cm⁻² and a 2500 h lifespan at 60% depth of discharge.

Half-Covered ‘Glitter-Cake’ AM@SE Composite: A Novel Electrode Design for High Energy Density All-Solid-State Batteries

2025-02-04T10:50:24+00:00

All-solid-state batteries (ASSBs) are pursued due to their potential for better safety and high energy density. However, the energy density of the cathode for ASSBs does not seem to be satisfactory due to the low utilization of active materials (AMs) at high loading. With small amount of solid electrolyte (SE) powder in the cathode, poor electrochemical performance is often observed due to contact loss and non-homogeneous distribution of AMs and SEs, leading to high tortuosity and limitation of lithium and electron transport pathways. Here, we propose a novel cathode design that can achieve high volumetric energy density of 1258 Wh L⁻¹ at high AM content of 85 wt% by synergizing the merits of AM@SE core–shell composite particles with conformally coated thin SE shell prepared from mechanofusion process and small SE particles. The core–shell structure with an intimate and thin SE shell guarantees high ionic conduction pathway while unharming the electronic conduction. In addition, small SE particles play the role of a filler that reduces the packing porosity in the cathode composite electrode as well as between the cathode and the SE separator layer. The systematic demonstration of the optimization process may provide understanding and guidance on the design of electrodes for ASSBs with high electrode density, capacity, and ultimately energy density.

Highlights:
1 A novel electrode design for high energy density all-solid-state batteries (ASSBs) is realized through the control of nano- and microstructures.
2 An active materials@solid electrolyte composite with a half-covered “glitter-cake” morphology is adopted to optimize the transport of electrons and ions in the electrode.
3 The optimized electrode design exhibited a volumetric energy density of 1258 Wh L⁻¹ at an active material content of 85 wt%, exceeding the performance of the reported ASSB cells.

NH4+-Modulated Cathodic Interfacial Spatial Charge Redistribution for High-Performance Dual-Ion Capacitors

2025-02-04T04:11:45+00:00

Compared with Zn²⁺, the current mainly reported charge carrier for zinc hybrid capacitors, small-hydrated-sized and light-weight NH₄⁺ is expected as a better one to mediate cathodic interfacial electrochemical behaviors, yet has not been unraveled. Here we propose an NH₄⁺-modulated cationic solvation strategy to optimize cathodic spatial charge distribution and achieve dynamic Zn²⁺/NH₄⁺ co-storage for boosting Zinc hybrid capacitors. Owing to the hierarchical cationic solvated structure in hybrid Zn(CF₃SO₃)₂–NH₄CF₃SO₃ electrolyte, high-reactive Zn²⁺ and small-hydrate-sized NH₄(H₂O)₄⁺ induce cathodic interfacial Helmholtz plane reconfiguration, thus effectively enhancing the spatial charge density to activate 20% capacity enhancement. Furthermore, cathodic interfacial adsorbed hydrated NH₄⁺ ions afford high-kinetics and ultrastable C‧‧‧H (NH₄⁺) charge storage process due to a much lower desolvation energy barrier compared with heavy and rigid Zn(H₂O)₆²⁺ (5.81 vs. 14.90 eV). Consequently, physical uptake and multielectron redox of Zn²⁺/NH₄⁺ in carbon cathode enable the zinc capacitor to deliver high capacity (240 mAh g⁻¹ at 0.5 A g⁻¹), large-current tolerance (130 mAh g⁻¹ at 50 A g⁻¹) and ultralong lifespan (400,000 cycles). This study gives new insights into the design of cathode–electrolyte interfaces toward advanced zinc-based energy storage.

Highlights:
1 Hierarchical Zn²⁺/NH⁴⁺ solvation structure induces cathodic interfacial Helmholtz plane reconfiguration to enhance spatial charge density and capacity storage.
2 Hydrated NH⁴⁺ ions afford high-kinetics and ultrastable C‧‧‧H charge storage due to a much lower desolvation energy barrier compared with large-sized Zn(H₂O)₆²⁺ (5.81 vs. 14.90 eV).
3 Interfacial Zn²⁺/NH⁴⁺ co-storage endow the hybrid capacitor with high capacity (240 mAh g⁻¹), large-current tolerance (50 A g⁻¹) and ultralong lifespan (400,000 cycles).

Layered Double Hydroxide Nanosheets Incorporated Hierarchical Hydrogen Bonding Polymer Networks for Transparent and Fire-Proof Ceramizable Coatings

2025-02-04T03:47:00+00:00

In recent decades, annual urban fire incidents, including those involving ancient wooden buildings burned, transportation, and solar panels, have increased, leading to significant loss of human life and property. Addressing this issue without altering the surface morphology or interfering with optical behavior of flammable materials poses a substantial challenge. Herein, we present a transparent, low thickness, ceramifiable nanosystem coating composed of a highly adhesive base (poly(SSS₁-co-HEMA₁)), nanoscale layered double hydroxide sheets as ceramic precursors, and supramolecular melamine di-borate as an accelerator. We demonstrate that this hybrid coating can transform into a porous, fire-resistant protective layer with a highly thermostable vitreous phase upon exposure to flame/heat source. A nanosystem coating of just ~ 100 μm thickness can significantly increase the limiting oxygen index of wood (Pine) to 37.3%, dramatically reduce total heat release by 78.6%, and maintain low smoke toxicity (CIT_G = 0.016). Detailed molecular force analysis, combined with a comprehensive examination of the underlying flame-retardant mechanisms, underscores the effectiveness of this coating. This work offers a strategy for creating efficient, environmentally friendly coatings with fire safety applications across various industries.

Highlights:
1 A transparent and ceramizable coating was developed by incorporating nano-layered double hydroxide nanosheets into hierarchical hydrogen bonding polymer networks.
2 The resulting coating composites demonstrated excellent high-temperature stability and fire resistance, effectively withstanding the direct exposure to a butane flame (~ 1100 °C) in air atmosphere.
3 The mechanisms behind the flame-retardant behavior and ceramicization behaviors were thoroughly investigated and explained.

Ultrasensitive Chemiresistive Gas Sensors Based on Dual-Mesoporous Zinc Stannate Composites for Room Temperature Rice Quality Monitoring

2025-02-04T03:34:07+00:00

The integration of dual-mesoporous structures, the construction of heterojunctions, and the incorporation of highly concentrated oxygen vacancies are pivotal for advancing metal oxide-based gas sensors. Nonetheless, achieving an optimal design that simultaneously combines mesoporous structures, precise heterojunction modulation, and controlled oxygen vacancies through a one-step process remains challenging. This study proposes an innovative method for fabricating zinc stannate semiconductors featuring dual-mesoporous structures and tunable oxygen vacancies via a direct solution precursor plasma spray technique. As a proof of concept, the resulting zinc stannate-based coatings are applied to detect 2-undecanone, a key biomarker for rice aging. Remarkably, the zinc oxide/zinc stannate heterojunctions with a well-defined secondary pore structure exhibit exceptional gas-sensing performance for 2-undecanone at room temperature. Furthermore, practical experiments indicate that the developed sensor effectively identifies adulteration in various rice varieties. These results underscore the potential of this method for designing metal oxides with tailored properties for high-performance gas sensors. The enhanced adsorption capacity and dual-mesoporous features of this semiconductor make it a promising candidate for sensing applications in agricultural food safety inspections.

Highlights:
1 Dual-mesoporous heterostructured semiconducting metal oxides were directly fabricated using a simple template-free method, optimizing porosity and improving surface area for enhanced gas-sensing.
2 The fabricated sensor exhibited high sensitivity (11.03 for 13 ppm), a rapid response time (21 s), and an impressively low theoretical detection limit (431 ppb) for 2-Undecanone at room temperature.
3 An innovative real-time method was developed for analyzing characteristic biomarkers of rice aging, enabling accurate and timely monitoring of rice quality.

Cellulose Elementary Fibrils as Deagglomerated Binder for High-Mass-Loading Lithium Battery Electrodes

2025-01-27T07:54:08+00:00

Amidst the ever-growing interest in high-mass-loading Li battery electrodes, a persistent challenge has been the insufficient continuity of their ion/electron conduction pathways. Here, we propose cellulose elementary fibrils (CEFs) as a class of deagglomerated binder for high-mass-loading electrodes. Derived from natural wood, CEF represents the most fundamental unit of cellulose with nanoscale diameter. The preparation of the CEFs involves the modulation of intermolecular hydrogen bonding by the treatment with a proton acceptor and a hydrotropic agent. This elementary deagglomeration of the cellulose fibers increases surface area and anionic charge density, thus promoting uniform dispersion with carbon conductive additives and suppressing interfacial side reactions at electrodes. Consequently, a homogeneous redox reaction is achieved throughout the electrodes. The resulting CEF-based cathode (overlithiated layered oxide (OLO) is chosen as a benchmark electrode active material) exhibits a high areal-mass-loading (50 mg cm^–2, equivalent to an areal capacity of 12.5 mAh cm^–2) and a high specific energy density (445.4 Wh kg^–1) of a cell, which far exceeds those of previously reported OLO cathodes. This study highlights the viability of the deagglomerated binder in enabling sustainable high-mass-loading electrodes that are difficult to achieve with conventional synthetic polymer binders.

Highlights:
1 Cellulose elementary fibrils (CEFs), the most fundamental unit of cellulose, are proposed as a deagglomerated binder for high-mass-loading Li battery electrodes.
2 The CEFs, due to their increased surface area and anionic charge density, promote uniform dispersion with carbon additives and mitigate interfacial side reactions in electrodes.
3 The CEF-based overlithiated layered oxide cathode exhibits a high areal-mass-loading (50 mg cm^–2) and a high specific energy density (445.4 Wh kg^–1) of a cell.

Revisiting Dipole-Induced Fluorinated-Anion Decomposition Reaction for Promoting a LiF-Rich Interphase in Lithium-Metal Batteries

2025-01-25T02:58:15+00:00

Building anion-derived solid electrolyte interphase (SEI) with enriched LiF is considered the most promising strategy to address inferior safety features and poor cyclability of lithium-metal batteries (LMBs). Herein, we discover that, instead of direct electron transfer from surface polar groups to bis(trifluoromethanesulfonyl)imide (TFSI⁻) for inducing a LiF-rich SEI, the dipole-induced fluorinated-anion decomposition reaction begins with the adsorption of Li ions and is highly dependent on their mobility on the polar surface. To demonstrate this, a single-layer graphdiyne on MXene (sGDY@MXene) heterostructure has been successfully fabricated and integrated into polypropylene separators. It is found that the adsorbed Li ions connect electron-donating sGDY@MXene to TFSI⁻, facilitating interfacial charge transfer for TFSI⁻ decomposition. However, this does not capture the entire picture. The sGDY@MXene also renders the adsorbed Li ions with high mobility, enabling them to reach optimal reaction sites and expedite their coordination processes with O on O=S=O and F on the broken –CF₃⁻, facilitating bond cleavage. In contrast, immobilized Li ions on the more lithiophilic pristine MXene retard these cleavage processes. Consequently, the decomposition reaction is accelerated on sGDY@MXene. This work highlights the dedicate balance between lithiophilicity and Li-ion mobility in effectively promoting a LiF-rich SEI for the long-term stability of LMBs.

Highlights:
1 Single-layer graphdiyne on MXene (sGDY@MXene) heterostructure was fabricated and integrated into polypropylene separators, directing a LiF-rich solid electrolyte interphase and long-term stability of lithium-metal anode.
2 Instead of direct electron transfer from surface polar groups to fluorinated anions, the adsorbed Li ions on sGDY@MXene act as dynamic bridges collaboratively connecting the electron-donating heterostructure to the anion and its derivatives, facilitating interface charge transfer.
3 Dedicate balance between lithiophilicity and high Li-ion mobility is the key to promote the dipole-induced fluorinated-anion decomposition.

Correction: Self-Assembly of Binderless MXene Aerogel for Multiple-Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding

2025-01-25T02:41:39+00:00

The severe dependence of traditional phase change materials (PCMs) on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios. Here, we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing. Subsequently, a series of MXene/ K⁺/paraffin wax (PW) phase change composites (PCCs) were obtained via vacuum impregnation in molten PW. The prepared MXene-based PCCs showed versatile applications from macroscale technologies, successfully transforming solar, electric, and magnetic energy into thermal energy stored as latent heat in the PCCs. Moreover, due to the absence of binder in the MXene-based aerogel, MK3@PW exhibits a prime solar–thermal conversion efficiency (98.4%). Notably, MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar–thermal–electric conversion (producing 206 mV of voltage with light radiation intensity of 200 mw cm⁻²). An excellent Joule heat performance (reaching 105 °C with an input voltage of 2.5 V) and responsive magnetic–thermal conversion behavior (a charging time of 11.8 s can achieve a thermal insulation effect of 285 s) for contactless thermotherapy were also demonstrated by the MK3@PW. Specifically, as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions, MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value (57.7 dB) than pure MXene aerogel/PW PCC (29.8 dB) with the same MXene mass. This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs.

Highlights:
1 This work proposes a tactic for improving the efficiency of thermal energy conversion and expanding the application scenarios of phase change materials by constructing non-binder and oriented MXene-K⁺ aerogel.
2 The prepared phase change composites (PCCs) can rapidly transform solar, electric, magnetic energy into latent heat for keeping warm, power generation, and thermal physiotherapy.
3 Owing to the suggested tactic, the prepared PCCs achieves ultrahigh energy storage density and realize 99.9998% electromagnetic wave energy attenuation.

Correction: A Broad Range Triboelectric Stiffness Sensor for Variable Inclusions Recognition

2025-01-14T12:51:53+00:00

With the development of artificial intelligence, stiffness sensors are extensively utilized in various fields, and their integration with robots for automated palpation has gained significant attention. This study presents a broad range self-powered stiffness sensor based on the triboelectric nanogenerator (Stiff-TENG) for variable inclusions in soft objects detection. The Stiff-TENG employs a stacked structure comprising an indium tin oxide film, an elastic sponge, a fluorinated ethylene propylene film with a conductive ink electrode, and two acrylic pieces with a shielding layer. Through the decoupling method, the Stiff-TENG achieves stiffness detection of objects within 1.0 s. The output performance and characteristics of the TENG for different stiffness objects under 4 mm displacement are analyzed. The Stiff-TENG is successfully used to detect the heterogeneous stiffness structures, enabling effective recognition of variable inclusions in soft object, reaching a recognition accuracy of 99.7%. Furthermore, its adaptability makes it well-suited for the detection of pathological conditions within the human body, as pathological tissues often exhibit changes in the stiffness of internal organs. This research highlights the innovative applications of TENG and thereby showcases its immense potential in healthcare applications such as palpation which assesses pathological conditions based on organ stiffness.

Highlights:
1 We propose a broad range triboelectric sensor system employing elastic sponge and shielding layers, which can realize fast stiffness recognition within 1.0 s at a low cost.
2 A novel algorithm is proposed for rapid stiffness identification by extracting signal characteristics, effectively reducing demand of computing resources.
3 The proposed sensor system can identify the multi-layer stiffness structure of objects, enabling effective recognition of variable inclusions in soft objects with an accuracy of 99.7%.

Tuning Isomerism Effect in Organic Bulk Additives Enables Efficient and Stable Perovskite Solar Cells

2025-01-14T12:36:58+00:00

Organic additives with multiple functional groups have shown great promise in improving the performance and stability of perovskite solar cells. The functional groups can passivate undercoordinated ions to reduce nonradiative recombination losses. However, how these groups synergistically affect the enhancement beyond passivation is still unclear. Specifically, isomeric molecules with different substitution patterns or molecular shapes remain elusive in designing new organic additives. Here, we report two isomeric carbazolyl bisphosphonate additives, 2,7-CzBP and 3,6-CzBP. The isomerism effect on passivation and charge transport process was studied. The two molecules have similar passivation effects through multiple interactions, e.g., P = O···Pb, P = O···H–N and N–H···I. 2,7-CzBP can further bridge the perovskite crystallites to facilitates charge transport. Power conversion efficiencies (PCEs) of 25.88% and 21.04% were achieved for 0.09 cm² devices and 14 cm² modules after 2,7-CzBP treatment, respectively. The devices exhibited enhanced operational stability maintaining 95% of initial PCE after 1000 h of continuous maximum power point tracking. This study of isomerism effect hints at the importance of tuning substitution positions and molecular shapes for organic additives, which paves the way for innovation of next-generation multifunctional aromatic additives.

Highlights:
1 By anchoring the perovskite sites with the functional groups of CzBP (P = O···Pb, N–H···I and P = O···N–H), the bulk nonradiative recombination is suppressed and ion migration is inhibited. Doping perovskite films with CzBP led to enhanced intercrystallite interactions in the bulk and improved photoluminescence quantum yield.
2 Using a typical electron-rich moiety as the π-linker to replace the classic alkyl spacer in CzBP facilitated the charge-carrier transport processes and the passivation effect of carbazole further contributed to high VOC. The optimized 2,7-CzBP-treated device achieves the highest power conversion efficiency (PCE) of 25.88%, with VOC of 1.189 V for 0.090 cm² and the perovskite solar cell module with a PCE of 21.04% for 14 cm².
3 For 2,7-CzBP, the more extended conjugation and the more linear molecular geometry result in a more effective improvement in the performance.

Biomimetic Micro-Nanostructured Evaporator with Dual-Transition-Metal MXene for Efficient Solar Steam Generation and Multifunctional Salt Harvesting

2025-01-07T02:06:00+00:00

Solar-driven interfacial evaporation is one of the most attractive approaches to addressing the global freshwater shortage. However, achieving an integrated high evaporation rate, salt harvesting, and multifunctionality in evaporator is still a crucial challenge. Here, a novel composite membrane with biomimetic micro-nanostructured superhydrophobic surface is designed via ultrafast laser etching technology. Attractively, the double‐transition‐metal (V_1/2Mo_1/2)₂CT_x MXene nanomaterials as a photothermal layer, exhibiting the enhanced photothermal conversion performance due to elevated joint densities of states, which enables high populations of photoexcited carrier relaxation and heat release, provides a new insight into the photothermal conversion mechanism for multiple principal element MXene. Hence, the (V_1/2Mo_1/2)₂CT_x MXene-200 composite membrane can achieve a high evaporation rate of 2.23 kg m⁻² h⁻¹ under one sun, owing to the enhanced “light trap” effect, photothermal conversion, and high-throughput water transfer. Synergetically, the membrane can induce the directed precipitation of salt at the membrane edge, thus enabling salt harvesting for recycling and zero-emission of brine water. Moreover, the composite membrane is endowed with excellent multifunctionality of anti‐/de‐icing, anti-fouling, and antibacterial, overcoming the disadvantage that versatility is difficult to be compatible. Therefore, the evaporator and the promising strategy hold great potential for the practical application of solar evaporation.

Highlights:
1 The design of composite membrane with biomimetic micro-nanostructured superhydrophobic surface and (V_1/2Mo_1/2)₂C MXene photothermal nanomaterials.
2 The double‐transition‐metal (V_1/2Mo_1/2)₂CT_x MXene exhibits enhanced photothermal conversion performance via the elevated joint densities of states.
3 The (V_1/2Mo_1/2)₂CT_x MXene-200 composite membrane achieves an evaporation rate of 2.23 kg m⁻² h⁻¹ under one sun, directed salt harvesting, and excellent multifunctionality of anti-/de-icing, anti-fouling, and antibacterial.

Ti3C2Tx Composite Aerogels Enable Pressure Sensors for Dialect Speech Recognition Assisted by Deep Learning

2025-01-02T07:27:41+00:00

Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection. However, current intelligent speech assistants based on pressure sensors can only recognize standard languages, which hampers effective communication for non-standard language people. Here, we prepare an ultralight Ti₃C₂T_x MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 kPa, rapid response/recovery time, and low hysteresis (13.69%). The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference, allowing for accurate recognition of six dialects (96.2% accuracy) and seven different words (96.6% accuracy) with the assistance of convolutional neural networks. This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.

Highlights:
1 Emphasized the innovation in both the material design and methodology between the sensing performance and mechanical properties.
2 The composite aerogel pressure sensors exhibited low hysteresis (13.69%), wide detection range (6.25 Pa-1200 kPa), and cyclic stability to acquire stable and accurate pronunciation signals.
3 Over 6888 and 4158 pronunciation signals were collected by the pressure sensor and utilized for training the convolutional neural network model, allowing for accurate recognition of six dialects (96.2% accuracy) and seven words (96.6% accuracy).

An Efficient and Flexible Bifunctional Dual-Band Electrochromic Device Integrating with Energy Storage

2024-12-29T10:36:07+00:00

Dual-band electrochromic devices capable of the spectral-selective modulation of visible (VIS) light and near-infrared (NIR) can notably reduce the energy consumption of buildings and improve the occupants' visual and thermal comfort. However, the low optical modulation and poor durability of these devices severely limit its practical applications. Herein, we demonstrate an efficient and flexible bifunctional dual-band electrochromic device which not only shows excellent spectral-selective electrochromic performance with a high optical modulation and a long cycle life, but also displays a high capacitance and a high energy recycling efficiency of 51.4%, integrating energy-saving with energy-storage. The nanowires structure and abundant oxygen-vacancies of oxygen-deficient tungsten oxide nanowires endows it high flexibility and a high optical modulation of 73.1% and 85.3% at 633 and 1200 nm respectively. The prototype device assembled can modulate the VIS light and NIR independently and effectively through three distinct modes with a long cycle life (3.3% capacity loss after 10,000 cycles) and a high energy-saving performance (8.8 °C lower than the common glass). Furthermore, simulations also demonstrate that our device outperforms the commercial low-emissivity glass in terms of energy-saving in most climatic zones around the world. Such windows represent an intriguing potential technology to improve the building energy efficiency.

Highlights:
1 A flexible dual-band electrochromic device with a high optical modulation and a long cycle life was reported.
2 The device assembled can modulate the visible light and near-infrared independently and effectively, showing higher energy-saving performance than commercial low-emissivity glass in most climatic zones around the world.
3 The flexible device also shows good energy storage and energy recycling performances, recycling 51.4% of the energy consumed in the coloration process for local reusing.

Hierarchically Porous Polypyrrole Foams Contained Ordered Polypyrrole Nanowire Arrays for Multifunctional Electromagnetic Interference Shielding and Dynamic Infrared Stealth

2024-12-29T10:22:17+00:00

As modern communication and detection technologies advance at a swift pace, multifunctional electromagnetic interference (EMI) shielding materials with active/positive infrared stealth, hydrophobicity, and electric-thermal conversion ability have received extensive attention. Meeting the aforesaid requirements simultaneously remains a huge challenge. In this research, the melamine foam (MF)/polypyrrole (PPy) nanowire arrays (MF@PPy) were fabricated via one-step electrochemical polymerization. The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays. Due to the upwardly grown PPy nanowire arrays, the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00° and outstanding stability under various harsh environments. Meanwhile, the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays. Furthermore, taking advantage of the high conductivity (128.2 S m⁻¹), the MF@PPy foam exhibited rapid Joule heating under 3 V, resulting in dynamic infrared stealth and thermal camouflage effects. More importantly, the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm² g⁻¹. Strong EMI shielding was put down to the hierarchically porous PPy structure, which offered outstanding impedance matching, conduction loss, and multiple attenuations. This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays, showing great applications in both military and civilian fields.

Highlights:
1 Hierarchical melamine foam (MF)/polypyrrole (PPy) nanowire arrays (MF@PPy) were fabricated by electrochemical polymerization.
2 The 3D porous PPy micro-skeleton and the 1D PPy nanowire arrays imparted the MF@PPy foams with high electromagnetic interference shielding performance of 19,928.57 dB cm² g⁻¹ via multiple attenuations.
3 The PPy nanowire arrays achieved multifunctional integration including hydrophobicity, thermal insulation, and dynamic infrared thermal camouflage properties.

Carbon Dots-Modified Hollow Mesoporous Photonic Crystal Materials for Sensitivity- and Selectivity-Enhanced Sensing of Chloroform Vapor

2024-12-29T05:33:09+00:00

Chloroform and other volatile organic pollutants have garnered widespread attention from the public and researchers, because of their potential harm to the respiratory system, nervous system, skin, and eyes. However, research on chloroform vapor sensing is still in its early stages, primarily due to the lack of specific recognition motif. Here we report a mesoporous photonic crystal sensor incorporating carbon dots-based nanoreceptor (HMSS@CDs-PCs) for enhanced chloroform sensing. The colloidal PC packed with hollow mesoporous silica spheres provides an interconnected ordered macro-meso-hierarchical porous structure, ideal for rapid gas sensing utilizing the photonic bandgap shift as the readout signal. The as-synthesized CDs with pyridinic-N-oxide functional groups adsorbed in the hollow mesoporous silica spheres are found to not only serve as the chloroform adsorption sites, but also a molecular glue that prevents crack formation in the colloidal PC. The sensitivity of HMSS@CDs-PCs sensor is 0.79 nm ppm⁻¹ and an impressively low limit of detection is 3.22 ppm, which are the best reported values in fast-response chloroform vapor sensor without multi-signal assistance. The positive response time is 7.5 s and the negative response time 9 s. Furthermore, relatively stable sensing can be maintained within a relative humidity of 20%–85%RH and temperature of 25–55 °C. This study demonstrates that HMSS@CDs-PCs sensors have practical application potential in indoor and outdoor chloroform vapor detection.

Highlights:
1 Uniform-sized hollow mesoporous silica spheres form colloidal photonic crystals for gas sensing.
2‘Nanoreceptors’ have been introduced for increasing the sensing sensitivity and specificity.
3 A chloroform gas sensor is created with a sensitivity of 0.79 nm ppm⁻¹ with a limit of detection of 3.22 ppm, which are the best reported values in fast-response chloroform vapor sensors without multi-signal assistance.

Breaking Solvation Dominance Effect Enabled by Ion–Dipole Interaction Toward Long-Spanlife Silicon Oxide Anodes in Lithium-Ion Batteries

2024-12-29T05:19:44+00:00

Micrometer-sized silicon oxide (SiO) anodes encounter challenges in large-scale applications due to significant volume expansion during the alloy/de-alloy process. Herein, an innovative deep eutectic electrolyte derived from succinonitrile is introduced to enhance the cycling stability of SiO anodes. Density functional theory calculations validate a robust ion–dipole interaction between lithium ions (Li⁺) and succinonitrile (SN). The cosolvent fluoroethylene carbonate (FEC) optimizes the Li⁺ solvation structure in the SN-based electrolyte with its weakly solvating ability. Molecular dynamics simulations investigate the regulating mechanism of ion–dipole and cation–anion interaction. The unique Li⁺ solvation structure, enriched with FEC and TFSI⁻, facilitates the formation of an inorganic–organic composite solid electrolyte interphase on SiO anodes. Micro-CT further detects the inhibiting effect on the SiO volume expansion. As a result, the SiO|LiCoO₂ full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes. This work presents an effective strategy for extending the cycle life of SiO anodes by designing a new SN-based deep eutectic electrolyte.

Highlights:
1 The succinonitrile-based deep eutectic electrolyte, characterized by strong ion–dipole interactions, can establish an anion-rich Li⁺ solvation structure while exhibiting high ionic conductivity and Li⁺ transference number.
2 Precisely regulating multiple ion–ion, ion–dipole, and dipole–dipole interactions facilitates the transition of the Li⁺ solvation structure from solvent dominance to anion dominance.
3 Optical microscopy and Micro-CT analysis can demonstrate that the anion-derived solid electrolyte interphase effectively mitigates the irreversible volume expansion of silicon oxide.

NiNC Catalysts in CO2-to-CO Electrolysis

2024-12-29T05:13:28+00:00

CO₂-to-CO electrolyzer technology converts carbon dioxide into carbon monoxide using electrochemical methods, offering significant environmental and energy benefits by aiding in greenhouse gas mitigation and promoting a carbon circular economy. Recent study by Strasser et al. in Nature Chemical Engineering presents a high-performance CO₂-to-CO electrolyzer utilizing a NiNC catalyst with nearly 100% faradaic efficiency, employing innovative diagnostic tools like the carbon crossover coefficient (CCC) to address transport-related failures and optimize overall efficiency. Strasser’s research demonstrates the potential of NiNC catalysts, particularly NiNC-IMI, for efficient CO production in CO₂-to-CO electrolyzers, highlighting their high selectivity and performance. However, challenges such as localized CO₂ depletion and mass transport limitations underscore the need for further optimization and development of diagnostic tools like CCC. Strategies for optimizing catalyst structure and operational parameters offer avenues for enhancing the performance and reliability of electrochemical CO₂ reduction catalysts.

Highlights:
1 NiNC catalysts achieve nearly 100% faradaic efficiency in CO₂-to-CO conversion.
2 The carbon crossover coefficient is introduced as a diagnostic tool for performance optimization.
3 Tandem electrolyzer design and mesoporous structures enhance product yields and efficiency.

Thermoelectric Modulation of Neat Ti3C2Tx MXenes by Finely Regulating the Stacking of Nanosheets

2024-12-29T04:59:34+00:00

Emerging two-dimensional MXenes have been extensively studied in a wide range of fields thanks to their superior electrical and hydrophilic attributes as well as excellent chemical stability and mechanical flexibility. Among them, the ultrahigh electrical conductivity (σ) and tunable band structures of benchmark Ti₃C₂T_x MXene demonstrate its good potential as thermoelectric (TE) materials. However, both the large variation of σ reported in the literature and the intrinsically low Seebeck coefficient (S) hinder the practical applications. Herein, this study has for the first time systematically investigated the TE properties of neat Ti₃C₂T_x films, which are finely modulated by exploiting different dispersing solvents, controlling nanosheet sizes and constructing composites. First, deionized water is found to be superior for obtaining closely packed MXene sheets relative to other polar solvents. Second, a simultaneous increase in both S and σ is realized via elevating centrifugal speed on MXene aqueous suspensions to obtain small-sized nanosheets, thus yielding an ultrahigh power factor up to ~ 156 μW m⁻¹ K⁻². Third, S is significantly enhanced yet accompanied by a reduction in σ when constructing MXene-based nanocomposites, the latter of which is originated from the damage to the intimate stackings of MXene nanosheets. Together, a correlation between the TE properties of neat Ti₃C₂T_x films and the stacking of nanosheets is elucidated, which would stimulate further exploration of MXene TEs.

Highlights:
1 Investigation of dispersing solvents on processing Ti₃C₂T_x thin films revealed that deionized water is superior to realize tight stacking and high orientation of MXene nanosheets.
2 A simultaneous elevation of Seebeck coefficient and electrical conductivity of neat Ti₃C₂T_x films is achieved by increasing the centrifugal speed of MXene aqueous suspensions due to the energy filtering effect.
3 Further construction of Ti₃C₂T_x nanocomposites significantly strengthens Seebeck coefficient yet disrupts the stacking of MXene nanosheets.

Ammonium Sensing Patch with Ultrawide Linear Range and Eliminated Interference for Universal Body Fluids Analysis

2024-12-24T03:47:03+00:00

Ammonium level in body fluids serves as one of the critical biomarkers for healthcare, especially those relative to liver diseases. The continuous and real-time monitoring in both invasive and non-invasive manners is highly desired, while the ammonium concentrations vary largely in different body fluids. Besides, the sensing reliability based on ion-selective biosensors can be significantly interfered by potassium ions. To tackle these challenges, a flexible and biocompatible sensing patch for wireless ammonium level sensing was reported with an ultrawide linear range for universal body fluids including blood, tears, saliva, sweat and urine. The as-prepared biocompatible sensors deliver a reliable sensitivity of 58.7 mV decade⁻¹ in the range of 1–100 mM and a desirable selectivity coefficient of 0.11 in the interference of potassium ions, attributed to the cross-calibration within the sensors array. The sensor’s biocompatibility was validated by the cell growth on the sensor surface (> 80%), hemolysis rates (< 5%), negligible cellular inflammatory responses and weight changes of the mice with implanted sensors. Such biocompatible sensors with ultrawide linear range and desirable selectivity open up new possibility of highly compatible biomarker analysis via different body fluids in versatile approaches.

Highlights:
1 The as-prepared sensors can detect NH₄⁺ in the body fluids with a high sensitivity of 58.7 mV decade⁻¹ and an ultrawide detection range of 1–100 mM.
2 The biocompatible sensors exhibit desirable biocompatibility and minimal toxicity for continuous and long-term monitoring.
3 The average detection error of the integrated and wireless biosensing patch was 13.2%, and body fluid detection accuracy is improved by more than 18% after cross-calibration.

Skin-Friendly Large Matrix Iontronic Sensing Meta-Fabric for Spasticity Visualization and Rehabilitation Training via Piezo-Ionic Dynamics

2024-12-20T05:26:04+00:00

Rehabilitation training is believed to be an effectual strategy that can reduce the risk of dysfunction caused by spasticity. However, achieving visualization rehabilitation training for patients remains clinically challenging. Herein, we propose visual rehabilitation training system including iontronic meta-fabrics with skin-friendly and large matrix features, as well as high-resolution image modules for distribution of human muscle tension. Attributed to the dynamic connection and dissociation of the meta-fabric, the fabric exhibits outstanding tactile sensing properties, such as wide tactile sensing range (0 ~ 300 kPa) and high-resolution tactile perception (50 Pa or 0.058%). Meanwhile, thanks to the differential capillary effect, the meta-fabric exhibits a “hitting three birds with one stone” property (dryness wearing experience, long working time and cooling sensing). Based on this, the fabrics can be integrated with garments and advanced data analysis systems to manufacture a series of large matrix structure (40 × 40, 1600 sensing units) training devices. Significantly, the tunability of piezo-ionic dynamics of the meta-fabric and the programmability of high-resolution imaging modules allow this visualization training strategy extendable to various common disease monitoring. Therefore, we believe that our study overcomes the constraint of standard spasticity rehabilitation training devices in terms of visual display and paves the way for future smart healthcare.

Highlights:
1 The iontronic meta-fabric exhibits a “hitting three birds with one stone” property, breaking through the bottleneck that traditional film materials (PDMS) cannot balance comfort and durability.
2 The meta-fabrics can be integrated with garments and advanced data analysis systems to manufacture a series of large matrix structure (> 40 × 40, 1600 sensing units) rehabilitation training devices, overcoming the bottleneck of low matrix integration of traditional iontronic devices (< 10 × 10, 100 sensing units).

Correction: Defects-Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

2024-12-20T05:11:32+00:00

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies, as well as veiled dielectric-responsive character, are instrumental in electromagnetic dissipation. Conventional methods, however, constrain their delicate constructions. Herein, an innovative alternative is proposed: carrageenan-assistant cations-regulated (CACR) strategy, which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix. This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction, benefiting the delicate construction of defects-rich heterostructures in M_xS_y/carbon composites (M-CAs). Impressively, these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and, simultaneously, induct local asymmetry of electronic structure to evoke large dipole moment, ultimately leading to polarization coupling, i.e., defect-type interfacial polarization. Such “Janus effect” (Janus effect means versatility, as in the Greek two-headed Janus) of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time. Consequently, the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm, compared to sulfur vacancies-free CAs without any dielectric response. Harnessing defects-rich heterostructures, this one-pot CACR strategy may steer the design and development of advanced nanomaterials, boosting functionality across diverse application domains beyond electromagnetic response.

Highlights:
1 A series of sulfides/carbon composites with sulfur vacancies-rich sulfides heterointerfaces are well-designed and developed via a simple one-pot carrageenan-assistant cations-regulated strategy.
2“Janus effect” of interfacial sulfur vacancies, which triggers strong defect-type interfacial polarization, are firstly intuitively confirmed by both theoretical and experimental investigations.
3 Optimized Co/Ni-carbon composites (CAs) imbued with sulfur vacancies-rich heterointerfaces displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm, compared to sulfur vacancies-free CAs without any dielectric response.

Concurrently Boosting Activity and Stability of Oxygen Reduction Reaction Catalysts via Judiciously Crafting Fe–Mn Dual Atoms for Fuel Cells

2024-12-16T05:15:20+00:00

The ability to unlock the interplay between the activity and stability of oxygen reduction reaction (ORR) represents an important endeavor toward creating robust ORR catalysts for efficient fuel cells. Herein, we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe–Mn dual-metal sites on N-doped carbon (denoted (FeMn-DA)–N–C) for both anion-exchange membrane fuel cells (AEMFC) and proton exchange membrane fuel cells (PEMFC). The (FeMn-DA)–N–C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N₄ and Mn-N₄ sites on the carbon surface, yielded via a facile doping-adsorption-pyrolysis route. The introduction of Mn carries several advantageous attributes: increasing the number of active sites, effectively anchoring Fe due to effective electron transfer to Mn (revealed by X-ray absorption spectroscopy and density-functional theory (DFT), thus preventing the aggregation of Fe), and effectively circumventing the occurrence of Fenton reaction, thus reducing the consumption of Fe. The (FeMn-DA)–N–C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO₄, respectively, as well as outstanding stability. As manifested by DFT calculations, the introduction of Mn affects the electronic structure of Fe, down-shifts the d-band Fe active center, accelerates the desorption of OH groups, and creates higher limiting potentials. The AEMFC and PEMFC with (FeMn-DA)–N–C as the cathode catalyst display high power densities of 1060 and 746 mW cm⁻², respectively, underscoring their promising potential for practical applications. Our study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.

Highlights:
1 Fe–Mn dual-atom catalysts exhibit superior oxygen reduction reaction (ORR) activity and stability, with high half-wave potentials in both alkaline and acidic conditions.
2 Synergistic Mn incorporation effectively anchors Fe atoms, mitigates the Fenton reaction, and enhances the durability of ORR catalysts.
3 Advanced characterization and density-functional theory calculations reveal Mn-induced electronic structure modifications, promoting superior ORR kinetics and active site performance.
4 (FeMn-DA)-N-C catalysts show remarkable potential for practical fuel cell applications.

Unlocking Novel Functionality: Pseudocapacitive Sensing in MXene-Based Flexible Supercapacitors

2024-12-10T07:45:30+00:00

Extensively explored for their distinctive pseudocapacitance characteristics, MXenes, a distinguished group of 2D materials, have led to remarkable achievements, particularly in the realm of energy storage devices. This work presents an innovative Pseudocapacitive Sensor. The key lies in switching the energy storage kinetics from pseudocapacitor to electrical double layer capacitor by employing the change of local pH (-log[H⁺]) in MXene-based flexible supercapacitors during bending. Pseudocapacitive sensing is observed in acidic electrolyte but absent in neutral electrolyte. Applied shearing during bending causes liquid-crystalline MXene sheets to increase in their degree of anisotropic alignment. With blocking of H⁺ mobility due to the higher diffusion barrier, local pH increases. The electrochemical energy storage kinetics transits from Faradaic chemical protonation (intercalation) to non-Faradaic physical adsorption. We utilize the phenomenon of capacitance change due to shifting energy storage kinetics for strain sensing purposes. The developed highly sensitive Pseudocapacitive Sensors feature a remarkable gauge factor (GF) of approximately 1200, far surpassing conventional strain sensors (GF: ~ 1 for dielectric-cap sensor). The introduction of the Pseudocapacitive Sensor represents a paradigm shift, expanding the application of pseudocapacitance from being solely confined to energy devices to the realm of multifunctional electronics. This technological leap enriches our understanding of the pseudocapacitance mechanism of MXenes, and will drive innovation in cutting-edge technology areas, including advanced robotics, implantable biomedical devices, and health monitoring systems.

Highlights:
1 We have discovered a novel phenomenon where the pseudocapacitance of flexible MXene supercapacitors changes sensitively in response to bending, leading to the development of Pseudocapacitive Sensors.
2 Pseudocapacitive Sensors repurpose supercapacitors as strain sensors, detecting capacitance changes from shifts between pseudocapacitance and electrical double layer capacitor. These highly sensitive sensors have a gauge factor of about 1200, far exceeding that of conventional strain sensors.

Revealing the Role of Hydrogen in Highly Efficient Ag-Substituted CZTSSe Photovoltaic Devices: Photoelectric Properties Modulation and Defect Passivation

2024-12-06T08:08:59+00:00

The presence of Sn_Zn-related defects in Cu₂ZnSn(S,Se)₄ (CZTSSe) absorber results in large irreversible energy loss and extra irreversible electron–hole non-radiative recombination, thus hindering the efficiency enhancement of CZTSSe devices. Although the incorporation of Ag in CZTSSe can effectively suppress the Sn_Zn-related defects and significantly improve the resulting cell performance, an excellent efficiency has not been achieved to date primarily owing to the poor electrical-conductivity and the low carrier density of the CZTSSe film induced by Ag substitution. Herein, this study exquisitely devises an Ag/H co-doping strategy in CZTSSe absorber via Ag substitution programs followed by hydrogen-plasma treatment procedure to suppress Sn_Zn defects for achieving efficient CZTSSe devices. In-depth investigation results demonstrate that the incorporation of H in Ag-based CZTSSe absorber is expected to improve the poor electrical-conductivity and the low carrier density caused by Ag substitution. Importantly, the C=O and O–H functional groups induced by hydrogen incorporation, serving as an electron donor, can interact with under-coordinated cations in CZTSSe material, effectively passivating the Sn_Zn-related defects. Consequently, the incorporation of an appropriate amount of Ag/H in CZTSSe mitigates carrier non-radiative recombination, prolongs minority carrier lifetime, and thus yields a champion efficiency of 14.74%, showing its promising application in kesterite-based CZTSSe devices.

Highlights:
1 The Ag/H co-doping strategy has been proposed to promote the performance of Cu₂ZnSn(S,Se)₄ (CZTSSe) devices.
2 The incorporation of H in Ag-based CZTSSe photovoltaic absorber is expected to improve the poor electrical conductivity and the low carrier density caused by Ag substitution.
3 Benefiting from the synergism of the excellent defect passivation effect and photoelectric properties complementary effect enabled by Ag/H co-doping, a champion device with 14.74% efficiency is achieved.

Hierarchical Polyimide Nonwoven Fabric with Ultralow-Reflectivity Electromagnetic Interference Shielding and High-Temperature Resistant Infrared Stealth Performance

2024-12-06T07:19:46+00:00

Designing and fabricating a compatible low-reflectivity electromagnetic interference (EMI) shielding/high-temperature resistant infrared stealth material possesses a critical significance in the field of military. Hence, a hierarchical polyimide (PI) nonwoven fabric is fabricated by alkali treatment, in-situ growth of magnetic particles and "self-activated" electroless Ag plating process. Especially, the hierarchical impedance matching can be constructed by systematically assembling Fe₃O₄/Ag-loaded PI nonwoven fabric (PFA) and pure Ag-coated PI nonwoven fabric (PA), endowing it with an ultralow-reflectivity EMI shielding performance. In addition, thermal insulation of fluffy three-dimensional (3D) space structure in PFA and low infrared emissivity of PA originated from Ag plating bring an excellent infrared stealth performance. More importantly, the strong bonding interaction between Fe₃O₄, Ag, and PI fiber improves thermal stability in EMI shielding and high-temperature resistant infrared stealth performance. Such excellent comprehensive performance makes it promising for military tents to protect internal equipment from electromagnetic interference stemmed from adjacent equipment and/or enemy, and inhibit external infrared detection.

Highlights:
1 Hierarchical polyimide (PI) nonwoven fabric is fabricated by alkali treatment, in-situ growth of magnetic particles, and "self-activated" electroless Ag plating process.
2 Impedance matching structure by assembling Fe₃O₄/Ag-loaded PI nonwoven fabric (PFA) and pure Ag-coated PI nonwoven fabric (PA) induces more electromagnetic waves enter PFA/PA and be dissipated.
3 The fluffy 3D space structure of PFA with strong adhesion interaction and low infrared emissivity of PA endow PFA/PA with excellent thermal stability in electromagnetic interference shielding and high-temperature resistant infrared stealth performance.

Anti-Swelling Polyelectrolyte Hydrogel with Submillimeter Lateral Confinement for Osmotic Energy Conversion

2024-12-06T07:04:17+00:00

Harvesting the immense and renewable osmotic energy with reverse electrodialysis (RED) technology shows great promise in dealing with the ever-growing energy crisis. One key challenge is to improve the output power density with improved trade-off between membrane permeability and selectivity. Herein, polyelectrolyte hydrogels (channel width, 2.2 nm) with inherent high ion conductivity have been demonstrated to enable excellent selective ion transfer when confined in cylindrical anodized aluminum pore with lateral size even up to the submillimeter scale (radius, 0.1 mm). The membrane permeability of the anti-swelling hydrogel can also be further increased with cellulose nanofibers. With real seawater and river water, the output power density of a three-chamber cell on behalf of repeat unit of RED system can reach up to 8.99 W m⁻² (per unit total membrane area), much better than state-of-the-art membranes. This work provides a new strategy for the preparation of polyelectrolyte hydrogel-based ion-selective membranes, owning broad application prospects in the fields of osmotic energy collection, electrodialysis, flow battery and so on.

Highlights:
1 Ionic polymers can directly serve as high-performance ion-selective membranes when it was physically confined within submillimeter-sized cylindrical pore.
2 The universality of this strategy is demonstrated in preparing cation/anion-selective membrane.
3 With real seawater and river water, the output power density of a three-chamber cell on behalf of repeat unit of reverse electrodialysis system can reach up to 8.99 W m⁻².

Carbon Nanofiber/Polyaniline Composite Aerogel with Excellent Electromagnetic Interference Shielding, Low Thermal Conductivity, and Extremely Low Heat Release

2024-12-02T06:03:03+00:00

The rapid development of communication technology and high-frequency electronic devices has created a need for more advanced electromagnetic interference (EMI) shielding materials. In response to this demand, a study has been conducted to develop multifunctional carbon nanofibers (CNFs)/polyaniline (PANI) aerogels with excellent electromagnetic interference shielding, flame retardancy, and thermal insulation performance. The process involved freeze-drying of electrospun CNFs and PANI nanoparticles followed by in situ growth PANI to coat the CNFs, creating the core–shell structured CNFs/PANI composite fiber and its hybrid aerogels (CP-3@PANI). The interaction between PANI and aniline (ANI) provides attachment sites, allowing additional ANI adsorption into the aerogel for in situ polymerization. This results in PANI uniformly covering the surface of the CNFs, creating a core–shell composite fiber with a flexible CNF core and PANI shell. This process enhances the utilization rate of the ANI monomer and increases the PANI content loaded onto the aerogel. Additionally, effective connections are established between the CNFs, forming a stable, conductive three-dimensional network structure. The prepared CP-3@PANI aerogels exhibit excellent EMI shielding efficiency (SE) of 85.4 dB and specific EMI SE (SE d⁻¹) of 791.2 dB cm³ g⁻¹ in the X-band. Due to the synergistic flame-retardant effect of CNFs, PANI, and the dopant (phytic acid), the CP-3@PANI aerogels demonstrate outstanding flame-retardant and thermal insulation properties, with a peak heat release rate (PHRR) as low as 7.8 W g⁻¹ and a total heat release of only 0.58 kJ g⁻¹. This study provides an effective strategy for preparing multifunctional integrated EMI shielding materials.

Highlights:
1 Using electrospun high-strength carbon nanofibers as the aerogel scaffold, high loading of polyaniline in the aerogel was achieved through seed polymerization, forming the core–shell structure fibers and simultaneously connecting the fibers as a stable conductive network.
2 Combining carbon-based materials with conductive polymers like polyaniline significantly improves shielding performance, achieving electromagnetic interference shielding efficiency of up to 84.5 dB and SE d⁻¹ values greater than 791.2 dB cm3 g⁻¹. Flame retardancy reduces PHRR by 65.8%, and thermal insulation with low thermal conductivity of 0.104 W m⁻¹ K⁻¹.

Ultrahigh Energy and Power Density in Ni–Zn Aqueous Battery via Superoxide-Activated Three-Electron Transfer

2024-12-02T05:52:18+00:00

Aqueous Ni–Zn microbatteries are safe, reliable and inexpensive but notoriously suffer from inadequate energy and power densities. Herein, we present a novel mechanism of superoxide-activated Ni substrate that realizes the redox reaction featuring three-electron transfers (Ni ↔ Ni³⁺). The superoxide activates the direct redox reaction between Ni substrate and KNiO₂ by lowering the reaction Gibbs free energy, supported by in-situ Raman and density functional theory simulations. The prepared chronopotentiostatic superoxidation-activated Ni (CPS-Ni) electrodes exhibit an ultrahigh capacity of 3.21 mAh cm⁻² at the current density of 5 mA cm⁻², nearly 8 times that of traditional one-electron processes electrodes. Even under the ultrahigh 200 mA cm⁻² current density, the CPS-Ni electrodes show 86.4% capacity retention with a Columbic efficiency of 99.2% after 10,000 cycles. The CPS-Ni||Zn microbattery achieves an exceptional energy density of 6.88 mWh cm⁻² and power density of 339.56 mW cm⁻². Device demonstration shows that the power source can continuously operate for more than 7 days in powering the sensing and computation intensive practical application of photoplethysmographic waveform monitoring. This work paves the way to the development of multi-electron transfer mechanisms for advanced aqueous Ni–Zn batteries with high capacity and long lifetime.

Highlights:
1 Efficient activation of Ni electrode employs chronopotentiostatic superoxidation.
2 Novel superoxide activation mechanism realizes the redox reaction with three-electron transfer (Ni ↔ Ni³⁺).
3 As-prepared CPS-Ni||Zn batteries exhibit simultaneously ultrahigh energy and power densities.

RGB Color-Discriminable Photonic Synapse for Neuromorphic Vision System

2024-12-02T05:41:34+00:00

To emulate the functionality of the human retina and achieve a neuromorphic visual system, the development of a photonic synapse capable of multispectral color discrimination is of paramount importance. However, attaining robust color discrimination across a wide intensity range, even irrespective of medium limitations in the channel layer, poses a significant challenge. Here, we propose an approach that can bestow the color-discriminating synaptic functionality upon a three-terminal transistor flash memory even with enhanced discriminating capabilities. By incorporating the strong induced dipole moment effect at the excitation, modulated by the wavelength of the incident light, into the floating gate, we achieve outstanding RGB color-discriminating synaptic functionality within a remarkable intensity range spanning from 0.05 to 40 mW cm⁻². This approach is not restricted to a specific medium in the channel layer, thereby enhancing its applicability. The effectiveness of this color-discriminating synaptic functionality is demonstrated through visual pre-processing of a photonic synapse array, involving the differentiation of RGB channels and the enhancement of image contrast with noise reduction. Consequently, a convolutional neural network can achieve an impressive inference accuracy of over 94% for Canadian-Institute-For-Advanced-Research-10 colorful image recognition task after the pre-processing. Our proposed approach offers a promising solution for achieving robust and versatile RGB color discrimination in photonic synapses, enabling significant advancements in artificial visual systems.

Highlights:
1 Photonic synapse capable of multispectral color discrimination is demonstrated.
2 Strong excited-state dipoles enable remarkable discrimination intensity (0.05–40 mW cm^-2).
3 This approach is not restricted to a specific medium in the channel layer, and convolutional neural network with synapses array achieves over 94% inference accuracy for Canadian-Institute-For-Advanced-Research-10 images.

Ligand Engineering Achieves Suppression of Temperature Quenching in Pure Green Perovskite Nanocrystals for Efficient and Thermostable Electroluminescence

2024-12-02T05:06:45+00:00

Formamidinium lead bromide (FAPbBr₃) perovskite nanocrystals (NCs) are promising for display and lighting due to their ultra-pure green emission. However, the thermal quenching will exacerbate their performance degradation in practical applications, which is a common issue for halide perovskites. Here, we reported the heat-resistant FAPbBr₃ NCs prepared by a ligand-engineered room-temperature synthesis strategy. An aromatic amine, specifically β-phenylethylamine (PEA) or 3-fluorophenylethylamine (3-F-PEA), was incoporated as the short-chain ligand to expedite the crystallization rate and control the size distribution of FAPbBr₃ NCs. Employing this ligand engineering approach, we synthesized high quality FAPbBr₃ NCs with uniform grain size and reduced long-chain alkyl ligands, resulting in substantially suppressed thermal quenching and enhanced carrier transportation in the perovskite NCs films. Most notably, more than 90% of the room temperature PL intensity in the 3-F-PEA modified FAPbBr₃ NCs film was preserved at 380 K. Consequently, we fabricated ultra-pure green EL devices with a room temperature external quantum efficiency (EQE) as high as 21.9% at the luminance of above 1,000 cd m⁻², and demonstrated less than 10% loss in EQE at 343 K. This study introduces a novel room temperature method to synthesize efficient FAPbBr₃ NCs with exceptional thermal stability, paving the way for advanced optoelectronic device applications.

Highlights:
1 The innovative synthesis of pure green FAPbBr₃ nanocrystals at room temperature was exploited by employing aromatic amine ligands to refine the perovskite nanocrystals with high quality and excellent optoelectronic properties.
2 The proposed ligand engineering strategy firstly realized the suppression of emission thermal quenching effect in the organic-inorganic hybrid FAPbBr₃ nanocrystals.
3 It was demonstrated that the FAPbBr₃ based light-emitting diodes achieved a room temperature external quantum efficiency (EQE) of 21.9% at the luminance of 1580 cd m^-2, and only presented less than 10% loss in EQE at a higher temperature of 343 K.

A Multifunctional Hydrogel with Multimodal Self-Powered Sensing Capability and Stable Direct Current Output for Outdoor Plant Monitoring Systems

2024-12-02T04:57:35+00:00

Smart farming with outdoor monitoring systems is critical to address food shortages and sustainability challenges. These systems facilitate informed decisions that enhance efficiency in broader environmental management. Existing outdoor systems equipped with energy harvesters and self-powered sensors often struggle with fluctuating energy sources, low durability under harsh conditions, non-transparent or non-biocompatible materials, and complex structures. Herein, a multifunctional hydrogel is developed, which can fulfill all the above requirements and build self-sustainable outdoor monitoring systems solely by it. It can serve as a stable energy harvester that continuously generates direct current output with an average power density of 1.9 W m⁻³ for nearly 60 days of operation in normal environments (24 °C, 60% RH), with an energy density of around 1.36 × 10⁷ J m⁻³. It also shows good self-recoverability in severe environments (45 °C, 30% RH) in nearly 40 days of continuous operation. Moreover, this hydrogel enables noninvasive and self-powered monitoring of leaf relative water content, providing critical data on evaluating plant health, previously obtainable only through invasive or high-power consumption methods. Its potential extends to acting as other self-powered environmental sensors. This multifunctional hydrogel enables self-sustainable outdoor systems with scalable and low-cost production, paving the way for future agriculture.

Highlights:
1 A simple and scalable fabricated hydrogel with multiple functionalities to realize self-sustainable outdoor monitoring solely by it for large-scale applications in precision agriculture.
2 Stable direct-current output without requirement on stochastic or temporal environmental energies, achieving an energy density of 1.36 × 10⁷ J m^–3 with continuous operation of 56.25 days in normal outdoor environment.
3 Self-powered noninvasive leaf relative water content monitoring and environmental sensing to evaluate plant health status with high durability and self-recoverability in severe environments.

Efficient and Stable Photoassisted Lithium-Ion Battery Enabled by Photocathode with Synergistically Boosted Carriers Dynamics

2024-12-01T08:41:32+00:00

Efficient and stable photocathodes with versatility are of significance in photoassisted lithium-ion batteries (PLIBs), while there is always a request on fast carrier transport in electrochemical active photocathodes. Present work proposes a general approach of creating bulk heterojunction to boost the carrier mobility of photocathodes by simply laser assisted embedding of plasmonic nanocrystals. When employed in PLIBs, it was found effective for synchronously enhanced photocharge separation and transport in light charging process. Additionally, experimental photon spectroscopy, finite difference time domain method simulation and theoretical analyses demonstrate that the improved carrier dynamics are driven by the plasmonic-induced hot electron injection from metal to TiO₂, as well as the enhanced conductivity in TiO₂ matrix due to the formation of oxygen vacancies after Schottky contact. Benefiting from these merits, several benchmark values in performance of TiO₂-based photocathode applied in PLIBs are set, including the capacity of 276 mAh g⁻¹ at 0.2 A g⁻¹ under illumination, photoconversion efficiency of 1.276% at 3 A g⁻¹, less capacity and Columbic efficiency loss even through 200 cycles. These results exemplify the potential of the bulk heterojunction strategy in developing highly efficient and stable photoassisted energy storage systems.

Highlights:
1 Developing a universal bulk heterojunction strategy to create oxygen vacancies by embedding laser-manufactured metal nanocrystals into the TiO₂ matrix.
2 Proposing a new mechanism based on plasmonic-induced hot electron injection and enhanced conductivity from Schottky contact-derived oxygen vacancies.
3 Establishing several benchmark values for the performance of TiO₂-based photocathodes in photoassisted lithium-ion batteries.

Dual-Donor-Induced Crystallinity Modulation Enables 19.23% Efficiency Organic Solar Cells

2024-12-01T04:38:50+00:00

Trap-assisted charge recombination is one of the primary limitations of restricting the performance of organic solar cells. However, effectively reducing the presence of traps in the photoactive layer remains challenging. Herein, wide bandgap polymer donor PTzBI-dF is demonstrated as an effective modulator for enhancing the crystallinity of the bulk heterojunction active layers composed of D18 derivatives blended with Y6, leading to dense and ordered molecular packings, and thus, improves photoluminescence quenching properties. As a result, the photovoltaic devices exhibit reduced trap-assisted charge recombination losses, achieving an optimized power conversion efficiency of over 19%. Besides the efficiency enhancement, the devices comprised of PTzBI-dF as a third component simultaneously attain decreased current leakage, improved charge carrier mobilities, and suppressed bimolecular charge recombination, leading to reduced energy losses. The advanced crystalline structures induced by PTzBI-dF and its characteristics, such as well-aligned energy level, and complementary absorption spectra, are ascribed to the promising performance improvements. Our findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providing guidelines for designing effective morphology modulators for high-performance organic solar cells.

Highlights:
1 By modulating the crystalline properties of the active layer with dual donors, the efficiency of organic solar cells reaches 19.23%.
2 The introduction of PTzBI-dF suppresses the accumulation of traps and charge recombination, allowing ternary devices to maintain 82% of their initial power conversion efficiency (PCE) after illumination for 800 h.
3 The dual-donor strategy for modulating the crystallinity of the active layer is applicable to a variety of Y6 derivatives, and the increase in PCE exceeds 1%.

A Fully-Printed Wearable Bandage-Based Electrochemical Sensor with pH Correction for Wound Infection Monitoring

2024-12-01T04:10:44+00:00

Wearable sensing systems have been designed to monitor health conditions in real-time by detecting analytes in human biofluids. Wound diagnosis remains challenging, necessitating suitable materials for high-performance wearable sensors to offer prompt feedback. Existing devices have limitations in measuring pH and the concentration of pH-dependent electroactive species simultaneously, which is crucial for obtaining a comprehensive understanding of wound status and optimizing biosensors. Therefore, improving materials and analysis system accuracy is essential. This article introduces the first example of a flexible array capable of detecting pyocyanin, a bacterial virulence factor, while correcting dynamic pH fluctuations. We demonstrate that this combined sensor enhances accuracy by mitigating the impact of pH variability on pyocyanin sensor response. Customized screen-printable inks were developed to enhance analytical performance. The analytical performances of two sensitive sensor systems (i.e., fully-printed porous graphene/multiwalled carbon nanotube (CNT) and polyaniline/CNT composites for pyocyanin and pH sensors) are evaluated. Partial least square regression is employed to analyze nonzero-order data arrays from square wave voltammetric and potentiometric measurements of pyocyanin and pH sensors to establish a predictive model for pyocyanin concentration in complex fluids. This sensitive and effective strategy shows potential for personalized applications due to its affordability, ease of use, and ability to adjust for dynamic pH changes.

Highlights:
1 The first example of a flexible array capable of detecting pyocyanin, a bacterial virulence factor, while correcting dynamic pH fluctuations.
2 Developed a screen-printable conductive nanocomposite ink for fabricating the pyocyanin sensor and utilized a polyaniline/carbon nanocomposite as a pH-sensitive film for the pH sensor.
3 Customized inks are advantageous in terms of flexible printed sensing array integrated onto a bandage surface, capable of monitoring both pyocyanin and pH levels in wound exudate.

Deciphering Water Oxidation Catalysts: The Dominant Role of Surface Chemistry over Reconstruction Degree in Activity Promotion

2024-11-29T04:09:25+00:00

Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction. The surface reconstruction has been widely observed in perovskite catalysts, and the reconstruction degree has been often correlated with the activity enhancement. Here, a systematic study on the roles of Fe substitution in activation of perovskite LaNiO₃ is reported. The substituting Fe content influences both current change tendency and surface reconstruction degree. LaNi_0.9Fe_0.1O₃ is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_1-xFe_xO₃ (x = 0.00, 0.10, 0.25, 0.50, 0.75, 1.00) series. The reconstructed LaNi_0.9Fe_0.1O₃ shows a higher intrinsic activity than most reported NiFe-based catalysts. Besides, density functional theory calculations reveal that Fe substitution can lower the O 2p level, which thus stabilize lattice oxygen in LaNi_0.9Fe_0.1O₃ and ensure its long-term stability. Furthermore, it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree. The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction. This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.

Highlights:
1 Demonstrate that the key factor to determine the activity of reconstructed surfaces is the surface chemistry, instead of reconstruction degree using the popular perovskite LaNi_1-xFe_xO₃ oxides as model materials.
2 Fe content can influence both the surface reconstruction degree, the activation degree, and the activity of reconstructed surfaces.
3 The oxygen evolution reaction activity of reconstructed catalysts is primarily governed by the chemistry of the reconstructed surface species.

Wafer-Scale Ag2S-Based Memristive Crossbar Arrays with Ultra-Low Switching-Energies Reaching Biological Synapses

2024-11-29T04:00:06+00:00

Memristive crossbar arrays (MCAs) offer parallel data storage and processing for energy-efficient neuromorphic computing. However, most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor (CMOS) technology still suffer from substantially larger energy consumption than biological synapses, due to the slow kinetics of forming conductive paths inside the memristive units. Here we report wafer-scale Ag₂S-based MCAs realized using CMOS-compatible processes at temperatures below 160 °C. Ag₂S electrolytes supply highly mobile Ag⁺ ions, and provide the Ag/Ag₂S interface with low silver nucleation barrier to form silver filaments at low energy costs. By further enhancing Ag⁺ migration in Ag₂S electrolytes via microstructure modulation, the integrated memristors exhibit a record low threshold of approximately − 0.1 V, and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses. The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics. Moreover, the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm. An impressive accuracy of 92.6% in image recognition simulations is demonstrated with the MCAs after the compensation. The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.

Highlights:
1 Wafer-scale integration of Ag₂S-based memristive crossbar arrays was demonstrated using complementary metal–oxide–semiconductor (CMOS) compatible processes below 160 °C.
2 A record-low threshold voltage for filament formation and an ultra-low switching-energy reaching that of biological synapses in wafer-scale CMOS-compatible memristive units were achieved.
3 The energy-efficient resistance switching was enabled by self-supply of mobile Ag⁺ ions in Ag₂S electrolytes and low silver-nucleation barrier at Ag/Ag₂S interface.

Bioinspired Ultrasensitive Flexible Strain Sensors for Real-Time Wireless Detection of Liquid Leakage

2024-11-29T03:42:32+00:00

Liquid leakage of pipeline networks not only results in considerable resource wastage but also leads to environmental pollution and ecological imbalance. In response to this global issue, a bioinspired superhydrophobic thermoplastic polyurethane/carbon nanotubes/graphene nanosheets flexible strain sensor (TCGS) has been developed using a combination of micro-extrusion compression molding and surface modification for real-time wireless detection of liquid leakage. The TCGS utilizes the synergistic effects of Archimedean spiral crack arrays and micropores, which are inspired by the remarkable sensory capabilities of scorpions. This design achieves a sensitivity of 218.13 at a strain of 2%, which is an increase of 4300%. Additionally, it demonstrates exceptional durability by withstanding over 5000 usage cycles. The robust superhydrophobicity of the TCGS significantly enhances sensitivity and stability in detecting small-scale liquid leakage, enabling precise monitoring of liquid leakage across a wide range of sizes, velocities, and compositions while issuing prompt alerts. This provides critical early warnings for both industrial pipelines and potential liquid leakage scenarios in everyday life. The development and utilization of bioinspired ultrasensitive flexible strain sensors offer an innovative and effective solution for the early wireless detection of liquid leakage.

Highlights:
1 Micro-extrusion compression molding and surface modification were proposed for the mass fabrication of a superhydrophobic thermoplastic polyurethane sensor (TCGS).
2 Inspired by scorpions, TCGS features Archimedean spiral crack arrays and micropores, achieving 218.13 sensitivity at 2% strain, a 4300% increase, and over 5000 usage cycles of durability.
3 The robust superhydrophobicity of TCGS improves sensitivity and stability for detecting small-scale liquid leakage, allowing precise monitoring across various sizes and compositions while providing early warnings in various scenarios.

Direct Photolithography of WOx Nanoparticles for High-Resolution Non-Emissive Displays

2024-11-29T02:18:01+00:00

High-resolution non-emissive displays based on electrochromic tungsten oxides (WO_x) are crucial for future near-eye virtual/augmented reality interactions, given their impressive attributes such as high environmental stability, ideal outdoor readability, and low energy consumption. However, the limited intrinsic structure of inorganic materials has presented a significant challenge in achieving precise patterning/pixelation at the micron scale. Here, we successfully developed the direct photolithography for WO_x nanoparticles based on in situ photo-induced ligand exchange. This strategy enabled us to achieve ultra-high resolution efficiently (line width < 4 µm, the best resolution for reported inorganic electrochromic materials). Additionally, the resulting device exhibited impressive electrochromic performance, such as fast response (< 1 s at 0 V), high coloration efficiency (119.5 cm² C⁻¹), good optical modulation (55.9%), and durability (> 3600 cycles), as well as promising applications in electronic logos, pixelated displays, flexible electronics, etc. The success and advancements presented here are expected to inspire and accelerate research and development (R&D) in high-resolution non-emissive displays and other ultra-fine micro-electronics.

Highlights:
1 Direct photolithography of electrochromic WO_x nanoparticles via in situ photo-induced ligand exchange is proposed and demonstrated.
2 The highest resolution among inorganic electrochromics (< 4 µm) is achieved, which is promising in high-resolution non-emissive displays.
3 The as-prepared device exhibits highly remarkable performance including rapid response, high coloration efficiency and durability.

Exploration of Gas-Dependent Self-Adaptive Reconstruction Behavior of Cu2O for Electrochemical CO2 Conversion to Multi-Carbon Products

2024-11-29T02:05:21+00:00

Structural reconstruction of electrocatalysts plays a pivotal role in catalytic performances for CO₂ reduction reaction (CO₂RR), whereas the behavior is by far superficially understood. Here, we report that CO₂ accessibility results in a universal self-adaptive structural reconstruction from Cu₂O to Cu@Cu_xO composites, ending with feeding gas-dependent microstructures and catalytic performances. The CO₂-rich atmosphere favors reconstruction for CO₂RR, whereas the CO₂-deficient one prefers that for hydrogen evolution reaction. With the assistance of spectroscopic analysis and theoretical calculations, we uncover a CO₂-induced passivation behavior by identifying a reduction-resistant but catalytic active Cu(I)-rich amorphous layer stabilized by *CO intermediates. Additionally, we find extra CO production is indispensable for the robust production of C₂H₄. An inverse correlation between durability and FE_CO/FE_C2H4 is disclosed, suggesting that the self-stabilization process involving the absorption of *CO intermediates on Cu(I) sites is essential for durable electrolysis. Guided by this insight, we design hollow Cu₂O nanospheres for durable and selective CO₂RR electrolysis in producing C₂H₄. Our work recognizes the previously overlooked passivation reconstruction and self-stabilizing behavior and highlights the critical role of the local atmosphere in modulating reconstruction and catalytic processes.

Highlights:
1 We revealed a universal self-adaptive structural reconstruction from Cu₂O to Cu@Cu_xO composites, ending with feeding gas-dependent microstructures and catalytic performances.
2 We uncovered a CO₂-induced passivation behavior by identifying a reduction-resistant but catalytic active Cu(I)-rich amorphous layer.
3 We designed and fabricated hollow Cu₂O nanospheres, demonstrating durable electrolysis at a partial current density of −200 mA cm⁻² in producing C₂H₄ with an FE of up to 61% at −0.6 V_RHE.

MXene Hybridized Polymer with Enhanced Electromagnetic Energy Harvest for Sensitized Microwave Actuation and Self-Powered Motion Sensing

2024-11-27T01:35:51+00:00

Polymeric microwave actuators combining tissue-like softness with programmable microwave-responsive deformation hold great promise for mobile intelligent devices and bionic soft robots. However, their application is challenged by restricted electromagnetic sensitivity and intricate sensing coupling. In this study, a sensitized polymeric microwave actuator is fabricated by hybridizing a liquid crystal polymer with Ti₃C₂T_x (MXene). Compared to the initial counterpart, the hybrid polymer exhibits unique space-charge polarization and interfacial polarization, resulting in significant improvements of 230% in the dielectric loss factor and 830% in the apparent efficiency of electromagnetic energy harvest. The sensitized microwave actuation demonstrates as the shortened response time of nearly 10 s, which is merely 13% of that for the initial shape memory polymer. Moreover, the ultra-low content of MXene (up to 0.15 wt%) benefits for maintaining the actuation potential of the hybrid polymer. An innovative self-powered sensing prototype that combines driving and piezoelectric polymers is developed, which generates real-time electric potential feedback (open-circuit potential of ~ 3 mV) during actuation. The polarization-dominant energy conversion mechanism observed in the MXene-polymer hybrid structure furnishes a new approach for developing efficient electromagnetic dissipative structures and shows potential for advancing polymeric electromagnetic intelligent devices.

Highlights:
1 An alternative electromagnetic attenuation pathway is proposed in the MXene-polymer hybrid structure, distinct from conduction loss, for generalizing the results to a wider range of electromagnetic-thermal driven soft materials and devices.
2 By efficiently harvesting and converting electromagnetic energy, the response time of the hybrid polymer to microwave exhibits 87% reduction with merely 0.15 wt% MXene.
3 A new mode of self-powered motion sensing based on deformation-driven piezoelectric effect is developed, enhancing the material’s intelligence.

Flexible Strain Sensors with Ultra-High Sensitivity and Wide Range Enabled by Crack-Modulated Electrical Pathways

2024-11-25T02:07:40+00:00

This study presents a breakthrough in flexible strain sensor technology with the development of an ultra-high sensitivity and wide-range sensor, addressing the critical challenge of reconciling sensitivity with measurement range. Inspired by the structure of bamboo slips, we introduce a novel approach that utilises liquid metal to modulate the electrical pathways within a cracked platinum fabric electrode. The resulting sensor demonstrates a gauge factor greater than 10⁸ and a strain measurement capability exceeding 100%. The integration of patterned liquid metal enables customisable tuning of the sensor’s response, while the porous fabric structure ensures superior comfort and air permeability for the wearer. Our design not only optimises the sensor’s performance but also enhances the electrical stability that is essential for practical applications. Through systematic investigation, we reveal the intrinsic mechanisms governing the sensor’s response, offering valuable insights for the design of wearable strain sensors. The sensor’s exceptional performance across a spectrum of applications, from micro-strain to large-strain detection, highlights its potential for a wide range of real-world uses, demonstrating a significant advancement in the field of flexible electronics.

Highlights:
1 A method is proposed for the modulation of electrical pathways in the cracks of stretchable electrodes using liquid metals, based on which ultra-high sensitivity (> 108) and large-range (> 100%) strain sensors are realised.
2 A secondary modulation of the response (or performance) of the sensor is proposed, allowing not only electrical modulation by liquid metal patterning during fabrication, but also mechanical modulation by pre-stretching at the time of use.
3 The air permeability and stability of the patterned liquid metal electrode region is optimised to enable air permeability similar to that of conventional fabrics and cycle durability in excess of 2000 cycles.

Low-Temperature Fabrication of Stable Black-Phase CsPbI3 Perovskite Flexible Photodetectors Toward Wearable Health Monitoring

2024-11-16T09:10:04+00:00

Flexible wearable optoelectronic devices fabricated from organic–inorganic hybrid perovskites significantly accelerate the development of portable energy, biomedicine, and sensing fields, but their poor thermal stability hinders further applications. Conversely, all-inorganic perovskites possess excellent thermal stability, but black-phase all-inorganic perovskite film usually requires high-temperature annealing steps, which increases energy consumption and is not conducive to the fabrication of flexible wearable devices. In this work, an unprecedented low-temperature fabrication of stable black-phase CsPbI₃ perovskite films is demonstrated by the in situ hydrolysis reaction of diphenylphosphinic chloride additive. The released diphenyl phosphate and chloride ions during the hydrolysis reaction significantly lower the phase transition temperature and effectively passivate the defects in the perovskite films, yielding high-performance photodetectors with a responsivity of 42.1 A W⁻¹ and a detectivity of 1.3 × 10¹⁴ Jones. Furthermore, high-fidelity image and photoplethysmography sensors are demonstrated based on the fabricated flexible wearable photodetectors. This work provides a new perspective for the low-temperature fabrication of large-area all-inorganic perovskite flexible optoelectronic devices.

Highlights:
1 Low-temperature fabrication of black-phase CsPbI₃ perovskite films is first demonstrated by using diphenylphosphinic chloride additive under 30–50 °C, arising from the steric effect and chloride insertion engineering.
2 Large-area high-quality all-inorganic perovskite films with fewer defects enhanced crystallographic orientation, and excellent environmental stability is fabricated.
3 The record performances are demonstrated for flexible wearable photodetectors with a responsivity of 42.1 A W⁻¹, a detectivity of 1.3 × 10¹⁴ Jones, high-fidelity image, photoplethysmography sensor functions, and high mechanical stability.

An Artificial Intelligence-Assisted Flexible and Wearable Mechanoluminescent Strain Sensor System

2024-11-16T08:52:47+00:00

The complex wiring, bulky data collection devices, and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices. To tackle these challenges, this work develops an artificial intelligence-assisted, wireless, flexible, and wearable mechanoluminescent strain sensor system (AIFWMLS) by integration of deep learning neural network-based color data processing system (CDPS) with a sandwich-structured flexible mechanoluminescent sensor (SFLC) film. The SFLC film shows remarkable and robust mechanoluminescent performance with a simple structure for easy fabrication. The CDPS system can rapidly and accurately extract and interpret the color of the SFLC film to strain values with auto-correction of errors caused by the varying color temperature, which significantly improves the accuracy of the predicted strain. A smart glove mechanoluminescent sensor system demonstrates the great potential of the AIFWMLS system in human gesture recognition. Moreover, the versatile SFLC film can also serve as a encryption device. The integration of deep learning neural network-based artificial intelligence and SFLC film provides a promising strategy to break the “color to strain value” bottleneck that hinders the practical application of flexible colorimetric strain sensors, which could promote the development of wearable and flexible strain sensors from laboratory research to consumer markets.

Highlights:
1 The sandwich-structured flexible mechanoluminescent sensor (SFLC) film shows great application potential as wireless wearable strain sensor and encryption device.
2 System-level integration of SFLC film with deep learning-based artificial intelligence enables fast and accurate interpretation of color data to strain values with automatic correction of errors caused by varying color temperatures.
3 The smart glove wearable sensor based on the SFLC film combined with deep learning neural network enables fast and accurate hand gesture recognition.

Ideal Bi-Based Hybrid Anode Material for Ultrafast Charging of Sodium-Ion Batteries at Extremely Low Temperatures

2024-11-13T07:49:05+00:00

Sodium-ion batteries have emerged as competitive substitutes for low-temperature applications due to severe capacity loss and safety concerns of lithium-ion batteries at − 20 °C or lower. However, the key capability of ultrafast charging at ultralow temperature for SIBs is rarely reported. Herein, a hybrid of Bi nanoparticles embedded in carbon nanorods is demonstrated as an ideal material to address this issue, which is synthesized via a high temperature shock method. Such a hybrid shows an unprecedented rate performance (237.9 mAh g⁻¹ at 2 A g⁻¹) at − 60 °C, outperforming all reported SIB anode materials. Coupled with a Na₃V₂(PO₄)₃ cathode, the energy density of the full cell can reach to 181.9 Wh kg⁻¹ at − 40 °C. Based on this work, a novel strategy of high-rate activation is proposed to enhance performances of Bi-based materials in cryogenic conditions by creating new active sites for interfacial reaction under large current.

Highlights:
1 Metallic nanoparticles with excellent size controllability and high loading rate are obtained via ultrafast high temperature shock method.
2 The Bi/CNRs-15 electrode exhibits an unprecedented rate performance (237.9 mAh g⁻¹ at 2 A g⁻¹) at − 60 °C, while the energy density of the full cell can reach to 181.9 Wh kg⁻¹ at − 40 °C.
3 A novel strategy of high-rate activation is proposed to obtain high capacity and superior stability at low temperature by creating new active sites for interfacial reaction.

Nanograting-Based Dynamic Structural Colors Using Heterogeneous Materials

2024-11-13T07:27:44+00:00

Dynamic structural colors can change in response to different environmental stimuli. This ability remains effective even when the size of the species responsible for the structural color is reduced to a few micrometers, providing a promising sensing mechanism for solving microenvironmental sensing problems in micro-robotics and microfluidics. However, the lack of dynamic structural colors that can encode rapidly, easily integrate, and accurately reflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensional dynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogel with an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollen state, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structural colors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamic structural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.

Highlights:
1 A 2.5-dimensional dynamic structural color based on nanogratings of heterogeneous materials was proposed by interweaving a pH-responsive hydrogel with IP-L photoresist.
2 The nanogrid structures exhibit brilliant tuneable structural color, high sensitivity, and ultrafast recovery speeds in response to pH.
3 The 4D printing-based grayscale design approach was proposed for the patterned encoding and array printing of dynamic structural colors, promoting their application in patterned printing, information encryption, and microfluidic chip sensing.

Electrode/Electrolyte Optimization-Induced Double-Layered Architecture for High-Performance Aqueous Zinc-(Dual) Halogen Batteries

2024-11-08T08:46:23+00:00

Aqueous zinc-halogen batteries are promising candidates for large-scale energy storage due to their abundant resources, intrinsic safety, and high theoretical capacity. Nevertheless, the uncontrollable zinc dendrite growth and spontaneous shuttle effect of active species have prohibited their practical implementation. Herein, a double-layered protective film based on zinc-ethylenediamine tetramethylene phosphonic acid (ZEA) artificial film and ZnF₂-rich solid electrolyte interphase (SEI) layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization. The ZEA-based artificial film shows strong affinity for the ZnF₂-rich SEI layer, therefore effectively suppressing the SEI breakage and facilitating the construction of double-layered protective film on the zinc metal anode. Such double-layered architecture not only modulates Zn²⁺ flux and suppresses the zinc dendrite growth, but also blocks the direct contact between the metal anode and electrolyte, thus mitigating the corrosion from the active species. When employing optimized metal anodes and electrolytes, the as-developed zinc-(dual) halogen batteries present high areal capacity and satisfactory cycling stability. This work provides a new avenue for developing aqueous zinc-(dual) halogen batteries.

Highlights:
1 A double-layered protective film based on zinc-based coordination compound and ZnF₂-rich solid electrolyte interphase layer has been successfully fabricated on the zinc metal anode via electrode/electrolyte synergistic optimization.
2 The double-layered architecture can effectively modulate Zn²⁺ flux and suppress the zinc dendrite growth, thus facilitating the uniform zinc deposition.
3 The as-developed zinc-(dual) halogen batteries based on double-layered protective film can present high areal capacity and satisfactory cycling stability.

Laser-Induced Highly Stable Conductive Hydrogels for Robust Bioelectronics

2024-11-07T01:59:24+00:00

Despite the promising progress in conductive hydrogels made with pure conducting polymer, great challenges remain in the interface adhesion and robustness in long-term monitoring. To address these challenges, Prof. Seung Hwan Ko and Taek-Soo Kim’s team introduced a laser-induced phase separation and adhesion method for fabricating conductive hydrogels consisting of pure poly(3,4-ethylenedioxythiophene):polystyrene sulfonate on polymer substrates. The laser-induced phase separation and adhesion treated conducting polymers can be selectively transformed into conductive hydrogels that exhibit wet conductivities of 101.4 S cm⁻¹ with a spatial resolution down to 5 μm. Moreover, they maintain impedance and charge-storage capacity even after 1 h of sonication. The micropatterned electrode arrays demonstrate their potential in long-term in vivo signal recordings, highlighting their promising role in the field of bioelectronics.

Highlights:
1 Stable adhesion of pure poly(3,4-ethylenedioxythiophene):polystyrene sulfonate hydrogel to polymer substrates was successfully achieved via a laser-induced phase separation and adhesion method.
2 The resulting conductive hydrogel exhibits a superior wet electrical conductivity up to 101.4 S cm⁻¹ and a spatial resolution down to 5 μm.
3 Such hydrogels hold great promise in robust bio-interfacing electrodes suitable for long-term high-fidelity signal monitoring.

Wafer-Scale Vertical 1D GaN Nanorods/2D MoS2/PEDOT:PSS for Piezophototronic Effect-Enhanced Self-Powered Flexible Photodetectors

2024-11-07T01:47:49+00:00

van der Waals (vdW) heterostructures constructed by low-dimensional (0D, 1D, and 2D) materials are emerging as one of the most appealing systems in next-generation flexible photodetection. Currently, hand-stacked vdW-type photodetectors are not compatible with large-area-array fabrication and show unimpressive performance in self-powered mode. Herein, vertical 1D GaN nanorods arrays (NRAs)/2D MoS₂/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly. The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W⁻¹ and a high detectivity of 1.2 × 10¹¹ Jones, as well as a fast response speed of 54/71 µs, thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction. Notably, the strain-tunable photodetection performances of device have been demonstrated. Impressively, the device at − 0.78% strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W⁻¹, a detectivity of 2.6 × 10¹¹ Jones, and response times of 40/45 µs, which are superior to the state-of-the-art self-powered flexible photodetectors. This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection, which performs well in flexible sensors.

Highlights:
1 Vertical 1D GaN nanorod arrays/2D MoS₂/PEDOT:PSS heterostructures in wafer scale have been fabricated for flexible photodetection firstly.
2 Self-powered flexible photodetector at compressive strain reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W⁻¹ and response times of 40/45 µs, which are superior to the state-of-the-art flexible devices.
3 This work not only provides a valuable strategy for the design and construction of tunable van der Waals heterostructures, but also opens a new opportunity for flexible sensors.

Defect Engineering with Rational Dopants Modulation for High-Temperature Energy Harvesting in Lead-Free Piezoceramics

2024-11-05T02:58:35+00:00

High temperature piezoelectric energy harvester (HT-PEH) is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors. However, simultaneously excellent performances, including high figure of merit (FOM), insulation resistivity (ρ) and depolarization temperature (T_d) are indispensable but hard to achieve in lead-free piezoceramics, especially operating at 250 °C has not been reported before. Herein, well-balanced performances are achieved in BiFeO₃–BaTiO₃ ceramics via innovative defect engineering with respect to delicate manganese doping. Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization, regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole, comprehensive excellent electrical performances (T_d = 340 °C, ρ_{250 °C} > 10⁷ Ω cm and FOM_{250 °C} = 4905 × 10^–15 m² N⁻¹) are realized at the solid solubility limit of manganese ions. The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250 °C with high energy conversion efficiency (η = 11.43%). These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements, paving a new way in developing self-powered wireless sensors working in HT environments.

Highlights:
1 The solution limit of manganese ion in BiFeO₃–BaTiO₃ (BF–BT) was determined by combining multiple advanced characterization methods.
2 The defect engineering associated with fine doping can realize the co-modulation of polarization configuration, iron oxidation state and domain orientation.
3 The BF–BT–0.2Mn piezoelectric energy harvester shows excellent power generation capacity at 250 °C, which is an important breakthrough for lead-free piezoelectric devices.

Multifunctional Nacre-Like Nanocomposite Papers for Electromagnetic Interference Shielding via Heterocyclic Aramid/MXene Template-Assisted In-Situ Polypyrrole Assembly

2024-11-05T02:26:16+00:00

Robust, ultra-flexible, and multifunctional MXene-based electromagnetic interference (EMI) shielding nanocomposite films exhibit enormous potential for applications in artificial intelligence, wireless telecommunication, and portable/wearable electronic equipment. In this work, a nacre-inspired multifunctional heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper with large-scale, high strength, super toughness, and excellent tolerance to complex conditions is fabricated through the strategy of HA/MXene hydrogel template-assisted in-situ assembly of PPy. Benefiting from the "brick-and-mortar" layered structure and the strong hydrogen-bonding interactions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa), outstanding toughness (57.6 MJ m⁻³), exceptional foldability, and structural stability against ultrasonication. By using the template effect of HA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly, the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dB at an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm² g⁻¹. In addition, the papers also have excellent applications in electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developing high-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.

Highlights:
1 The large-scale, high-strength, super-tough, and multifunctional nacre-like heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite papers were fabricated using the in-situ assembly of PPy onto the HA/MXene hydrogel template.
2 The "brick-and-mortar" layered structure and abundant hydrogen-bonding interactions among MXene, PPy, and HA respond cooperatively to external stress and effectively increase the mechanical properties of HMP nanocomposite papers.
3 The templating effect from HA/MXene was utilized to guide the assembly of conducting polymers, leading to high electrical conductivity and outstanding electromagnetic interference shielding performance.

Inter-Skeleton Conductive Routes Tuning Multifunctional Conductive Foam for Electromagnetic Interference Shielding, Sensing and Thermal Management

2024-11-05T02:11:24+00:00

Conductive polymer foam (CPF) with excellent compressibility and variable resistance has promising applications in electromagnetic interference (EMI) shielding and other integrated functions for wearable electronics. However, its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation. Here, an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression. Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton (denoted as AMLM-PM foam). Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films. Therefore, the resistance change of AMLM-PM reaches four orders of magnitude under compression. Moreover, the inter-skeleton conductive films can improve the mechanical strength of foam, prevent the leakage of liquid metal and increase the scattering area of EM wave. AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness, solving the problem of traditional CPFs upon compression. The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function.

Highlights:
1 Unique inter-skeleton conductive films are constructed in polymer foam.
2 The resistance change of the foam can reach four orders of magnitude under compression.
3 This foam exhibits strain-adaptive electromagnetic interference shielding performance, anti-interference pressure sensor with high sensitivity over a wide pressure range and compression-regulated Joule heating function.

Scalable Ir-Doped NiFe2O4/TiO2 Heterojunction Anode for Decentralized Saline Wastewater Treatment and H2 Production

2024-11-04T04:02:41+00:00

Wastewater electrolysis cells (WECs) for decentralized wastewater treatment/reuse coupled with H₂ production can reduce the carbon footprint associated with transportation of water, waste, and energy carrier. This study reports Ir-doped NiFe₂O₄ (NFI, ~ 5 at% Ir) spinel layer with TiO₂ overlayer (NFI/TiO₂), as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell. In dilute (0.1 M) NaCl solutions, the NFI/TiO₂ marks superior activity and selectivity for chlorine evolution reaction, outperforming the benchmark IrO₂. Robust operation in near-neutral pH was confirmed. Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO₂ which serves both as the primary site for Cl⁻ chemisorption and a protective layer for NFI as an ohmic contact. Galvanostatic electrolysis of NH₄⁺-laden synthetic wastewater demonstrated that NFI/TiO₂ not only achieves quasi-stoichiometric NH₄⁺-to-N₂ conversion, but also enhances H₂ generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine. The scaled-up WEC with NFI/TiO₂ was demonstrated for electrolysis of toilet wastewater.

Highlights:
1 Ir-doped NiFe₂O₄ (NFI) spinel with TiO₂ heterojunction overlayer brought about outstanding chlorine evolution reaction in circumneutral pH.
2 Electroanalyses including operando X-ray absorption spectroscopy uncovered the active role of TiO₂ for Cl⁻ chemisorption.
3 NFI/TiO₂ anode boosted both NH₄⁺-to-N₂ conversion and H₂ generation in wastewater, and the practical applicability was confirmed with scaled-up anodes and real wastewater.

A Flexible Smart Healthcare Platform Conjugated with Artificial Epidermis Assembled by Three-Dimensionally Conductive MOF Network for Gas and Pressure Sensing

2024-10-27T04:46:53+00:00

The rising flexible and intelligent electronics greatly facilitate the noninvasive and timely tracking of physiological information in telemedicine healthcare. Meticulously building bionic-sensitive moieties is vital for designing efficient electronic skin with advanced cognitive functionalities to pluralistically capture external stimuli. However, realistic mimesis, both in the skin’s three-dimensional interlocked hierarchical structures and synchronous encoding multistimuli information capacities, remains a challenging yet vital need for simplifying the design of flexible logic circuits. Herein, we construct an artificial epidermal device by in situ growing Cu₃(HHTP)₂ particles onto the hollow spherical Ti₃C₂T_x surface, aiming to concurrently emulate the spinous and granular layers of the skin’s epidermis. The bionic Ti₃C₂T_x@Cu₃(HHTP)₂ exhibits independent NO₂ and pressure response, as well as novel functionalities such as acoustic signature perception and Morse code-encrypted message communication. Ultimately, a wearable alarming system with a mobile application terminal is self-developed by integrating the bimodular senor into flexible printed circuits. This system can assess risk factors related with asthmatic, such as stimulation of external NO₂ gas, abnormal expiratory behavior and exertion degrees of fingers, achieving a recognition accuracy of 97.6% as assisted by a machine learning algorithm. Our work provides a feasible routine to develop intelligent multifunctional healthcare equipment for burgeoning transformative telemedicine diagnosis.

Highlights:
1 A smart wearable alarming system integrated artificial epidermal device for pluralistically identifying asthmatic attack risk factors, achieving a 97.6% classification accuracy as assisted by machine learning algorithm.
2 A meticulous mimicry both in the advanced structural attributes and encoding information abilities of the skin was adopted to design a novel artificial epidermal device by integrating conductive Cu₃(HHTP)₂ coupled with spherical Ti₃C₂T_x.
3 The bioinspired Ti₃C₂T_x@Cu₃(HHTP)₂ sensors can independently perceive NO₂ gas and pressure-triggered stimuli.

Dynamic Regulation of Hydrogen Bonding Networks and Solvation Structures for Synergistic Solar-Thermal Desalination of Seawater and Catalytic Degradation of Organic Pollutants

2024-10-26T09:31:30+00:00

Although solar steam generation strategy is efficient in desalinating seawater, it is still challenging to achieve continuous solar-thermal desalination of seawater and catalytic degradation of organic pollutants. Herein, dynamic regulations of hydrogen bonding networks and solvation structures are realized by designing an asymmetric bilayer membrane consisting of a bacterial cellulose/carbon nanotube/Co₂(OH)₂CO₃ nanorod top layer and a bacterial cellulose/Co₂(OH)₂CO₃ nanorod (BCH) bottom layer. Crucially, the hydrogen bonding networks inside the membrane can be tuned by the rich surface –OH groups of the bacterial cellulose and Co₂(OH)₂CO₃ as well as the ions and radicals in situ generated during the catalysis process. Moreover, both SO₄²⁻ and HSO₅⁻ can regulate the solvation structure of Na⁺ and be adsorbed more preferentially on the evaporation surface than Cl⁻, thus hindering the de-solvation of the solvated Na⁺ and subsequent nucleation/growth of NaCl. Furthermore, the heat generated by the solar-thermal energy conversion can accelerate the reaction kinetics and enhance the catalytic degradation efficiency. This work provides a flow-bed water purification system with an asymmetric solar-thermal and catalytic membrane for synergistic solar thermal desalination of seawater/brine and catalytic degradation of organic pollutants.

Highlights:
1 A flow-bed water purification system with an asymmetric solar-thermal and catalytic membrane is designed for synergistic solar-thermal desalination of seawater/brine and catalytic degradation of organic pollutants.
2 The hydrogen bonding networks can be regulated by the abundant surface –OH groups and the in situ generated ions and radicals during the degradation process for promoting solar-driven steam generation.
3 The de-solvation of solvated Na⁺ and subsequent nucleation/growth of NaCl are effectively inhibited by SO₄²⁻/HSO₅⁻ ions.

Graphene Aerogel Composites with Self-Organized Nanowires-Packed Honeycomb Structure for Highly Efficient Electromagnetic Wave Absorption

2024-10-26T09:19:32+00:00

With vigorous developments in nanotechnology, the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers. Herein, a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity. The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires (SiC_nws) grown in situ, while boron nitride (BN) interfacial structure is introduced on graphene nanoplates. The unique composite structure forces multiple scattering of incident EMWs, ensuring the combined effects of interfacial polarization, conduction networks, and magnetic-dielectric synergy. Therefore, the as-prepared composites present a minimum reflection loss value of − 37.8 dB and a wide effective absorption bandwidth (EAB) of 9.2 GHz (from 8.8 to 18.0 GHz) at 2.5 mm. Besides, relying on the intrinsic high-temperature resistance of SiC_nws and BN, the EAB also remains above 5.0 GHz after annealing in air environment at 600 °C for 10 h.

Highlights:
1 A new strategy for elaborate regulation of microstructure was successfully introduced by the ice template‑assisted 3D printing and chemical vapor deposition strategy, including graphene nanoplate/silicon carbide nanowires hierarchical porous structure and graphene nanoplate/boron nitride composite heterogeneous interface.
2 The composite exhibits excellent electromagnetic wave absorption performance with an RLmin of -37.8 dB and an EABmax of 9.2 GHz (from 8.8 to 18.0 GHz) at 2.5 mm. And the high-temperature absorption stability makes it a promising absorber candidate under high temperature and oxidizing atmosphere.

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N-RGO for Boosting Electromagnetic Wave Absorption

2024-10-21T02:40:49+00:00

Developing effective strategies to regulate graphene's conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption (EMWA) field. Based on the unique energy band structure of graphene, regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible solution. Herein, metal-nitrogen doping reduced graphene oxide (M–N-RGO) was prepared by embedding a series of single metal atoms M–N₄ sites (M = Mn, Fe, Co, Ni, Cu, Zn, Nb, Cd, and Sn) in RGO using an N-coordination atom-assisted strategy. These composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA performance. The results showed that the minimum reflection loss (RL_min) of Fe–N-RGO reaches − 74.05 dB (2.0 mm) and the maximum effective absorption bandwidth (EAB_max) is 7.05 GHz (1.89 mm) even with a low filler loading of only 1 wt%. Combined with X-ray absorption spectra (XAFS), atomic force microscopy, and density functional theory calculation analysis, the Fe–N₄ can be used as the polarization center to increase dipole polarization, interface polarization and defect-induced polarization due to d-p orbital hybridization and structural distortion. Moreover, electron migration within the Fe further leads to conduction loss, thereby synergistically promoting energy attenuation. This study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties, which provides an important basis for further investigation of the loss mechanism.

Highlights:
1 Single-atom Fe–N₄ sites embedded into graphene were successfully synthesized to exert the dielectric properties of graphene.
2 The absorption mechanisms of metal-nitrogen doping reduced graphene oxide mainly include enhanced dipole polarization, interface polarization, conduction loss and defect-induced polarization.
3 Excellent reflection loss of − 74.05 dB (2.0 mm) and broad effective absorption bandwidth of 7.05 GHz (1.89 mm, with filler loading only 1 wt%) were obtained.

Sulfolane-Based Flame-Retardant Electrolyte for High-Voltage Sodium-Ion Batteries

2024-10-21T02:26:50+00:00

Sodium-ion batteries hold great promise as next-generation energy storage systems. However, the high instability of the electrode/electrolyte interphase during cycling has seriously hindered the development of SIBs. In particular, an unstable cathode–electrolyte interphase (CEI) leads to successive electrolyte side reactions, transition metal leaching and rapid capacity decay, which tends to be exacerbated under high-voltage conditions. Therefore, constructing dense and stable CEIs are crucial for high-performance SIBs. This work reports localized high-concentration electrolyte by incorporating a highly oxidation-resistant sulfolane solvent with non-solvent diluent 1H, 1H, 5H-octafluoropentyl-1, 1, 2, 2-tetrafluoroethyl ether, which exhibited excellent oxidative stability and was able to form thin, dense and homogeneous CEI. The excellent CEI enabled the O3-type layered oxide cathode NaNi_1/3Mn_1/3Fe_1/3O₂ (NaNMF) to achieve stable cycling, with a capacity retention of 79.48% after 300 cycles at 1 C and 81.15% after 400 cycles at 2 C with a high charging voltage of 4.2 V. In addition, its nonflammable nature enhances the safety of SIBs. This work provides a viable pathway for the application of sulfolane-based electrolytes on SIBs and the design of next-generation high-voltage electrolytes.

Highlights:
1 NaTFSI/SUL:OTE:FEC facilitates the formation of S, N-rich, dense and robust cathode–electrolyte interphase on NaNMF cathode, which improves the cycling stability under high voltage.
2 By utilizing NaTFSI/SUL:OTE:FEC, the Na||NaNMF batteries achieved an impressive retention of 81.15% after 400 cycles at 2 C with the cutoff voltage of 4.2 V.
3 The study offers a reference for the utilization of sulfolane-based electrolytes in sodium-ion batteries (SIBs), while the nonflammability of the NaTFSI/SUL:OTE:FEC enhances the safety of SIBs.

Gradient-Layered MXene/Hollow Lignin Nanospheres Architecture Design for Flexible and Stretchable Supercapacitors

2024-10-21T02:04:58+00:00

With the rapid development of flexible wearable electronics, the demand for stretchable energy storage devices has surged. In this work, a novel gradient-layered architecture was design based on single-pore hollow lignin nanospheres (HLNPs)-intercalated two-dimensional transition metal carbide (Ti₃C₂T_x MXene) for fabricating highly stretchable and durable supercapacitors. By depositing and inserting HLNPs in the MXene layers with a bottom-up decreasing gradient, a multilayered porous MXene structure with smooth ion channels was constructed by reducing the overstacking of MXene lamella. Moreover, the micro-chamber architecture of thin-walled lignin nanospheres effectively extended the contact area between lignin and MXene to improve ion and electron accessibility, thus better utilizing the pseudocapacitive property of lignin. All these strategies effectively enhanced the capacitive performance of the electrodes. In addition, HLNPs, which acted as a protective phase for MXene layer, enhanced mechanical properties of the wrinkled stretchable electrodes by releasing stress through slip and deformation during the stretch-release cycling and greatly improved the structural integrity and capacitive stability of the electrodes. Flexible electrodes and symmetric flexible all-solid-state supercapacitors capable of enduring 600% uniaxial tensile strain were developed with high specific capacitances of 1273 mF cm⁻² (241 F g⁻¹) and 514 mF cm⁻² (95 F g⁻¹), respectively. Moreover, their capacitances were well preserved after 1000 times of 600% stretch-release cycling. This study showcased new possibilities of incorporating biobased lignin nanospheres in energy storage devices to fabricate stretchable devices leveraging synergies among various two-dimensional nanomaterials.

Highlights:
1 A novel gradient-layered architecture based on single-pore hollow lignin nanospheres (HLNPs)-intercalated MXene layers was created to fabricate highly stretchable (600%) and durable (1000 cycling) supercapacitor electrodes.
2 The architecture reduced the overstacking of MXene, and the micro-chamber structure of HLNPs better utilized lignin’s pseudocapacitive property to improve ion and electron accessibility (specific capacitance reached 1273 mF cm⁻²).
3 HLNPs enhanced mechanical durability and capacitive stability of the integrated wrinkled electrodes during the stretch-release cycling.

Ultra-High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception

2024-10-21T01:55:39+00:00

Monitoring minuscule mechanical signals, both in magnitude and direction, is imperative in many application scenarios, e.g., structural health monitoring and robotic sensing systems. However, the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix, and achieving sensitivity for detecting micrometer-scale deformations is also challenging. Herein, we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement, capable of detecting minute anisotropic deformations. The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%, thereby enabling its utility in accurately discerning the 5 μm-height wrinkles in thin films and in monitoring human pulse waves. The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase. Additionally, when integrated with machine learning techniques, the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100% accuracy. The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli, offering a novel perspective for enhancing recognition accuracy.

Highlights:
1 A novel anisotropic sensor with oriented piezoelectric filaments was prepared, capable of detecting both the magnitude and direction of micro-deformations.
2 Due to the efficient load transfer of continuous fibers and the formation of porous ferroelectrets, an ultra-low strain detection limit of 0.06% was achieved in the sensor.
3 Given the sensor's ultra-low detection limit and deformation direction sensing capability, we developed the sensor for detecting micron-scale deformations in thin-film structures and for robotic tactile sensing applications.

A Rapid Adaptation Approach for Dynamic Air-Writing Recognition Using Wearable Wristbands with Self-Supervised Contrastive Learning

2024-10-21T01:40:52+00:00

Wearable wristband systems leverage deep learning to revolutionize hand gesture recognition in daily activities. Unlike existing approaches that often focus on static gestures and require extensive labeled data, the proposed wearable wristband with self-supervised contrastive learning excels at dynamic motion tracking and adapts rapidly across multiple scenarios. It features a four-channel sensing array composed of an ionic hydrogel with hierarchical microcone structures and ultrathin flexible electrodes, resulting in high-sensitivity capacitance output. Through wireless transmission from a Wi-Fi module, the proposed algorithm learns latent features from the unlabeled signals of random wrist movements. Remarkably, only few-shot labeled data are sufficient for fine-tuning the model, enabling rapid adaptation to various tasks. The system achieves a high accuracy of 94.9% in different scenarios, including the prediction of eight-direction commands, and air-writing of all numbers and letters. The proposed method facilitates smooth transitions between multiple tasks without the need for modifying the structure or undergoing extensive task-specific training. Its utility has been further extended to enhance human–machine interaction over digital platforms, such as game controls, calculators, and three-language login systems, offering users a natural and intuitive way of communication.

Highlights:
1 Utilizing self-supervised learning, the proposed wearable wristband with a four-channel sensing array and wireless transmission module is developed for tracking air-writing and dynamic gestures.
2 The model can learn prior features from unlabeled signals of random wrist movements, significantly reducing the dependency on extensive labeled data for training.
3 The wristband system rapidly adapts to multiple scenarios after fine-tuning using few-shot data, enhancing user interaction through natural and intuitive communication.

Magneto-Dielectric Synergy and Multiscale Hierarchical Structure Design Enable Flexible Multipurpose Microwave Absorption and Infrared Stealth Compatibility

2024-10-21T01:31:22+00:00

Developing advanced stealth devices to cope with radar-infrared (IR) fusion detection and diverse application scenarios is increasingly demanded, which faces significant challenges due to conflicting microwave and IR cloaking mechanisms and functional integration limitations. Here, we propose a multiscale hierarchical structure design, integrating wrinkled MXene IR shielding layer and flexible Fe₃O₄@C/PDMS microwave absorption layer. The top wrinkled MXene layer induces the intensive diffuse reflection effect, shielding IR radiation signals while allowing microwave to pass through. Meanwhile, the permeable microwaves are assimilated into the bottom Fe₃O₄@C/PDMS layer via strong magneto-electric synergy. Through theoretical and experimental optimization, the assembled stealth devices realize a near-perfect stealth capability in both X-band (8–12 GHz) and long-wave infrared (8–14 µm) wavelength ranges. Specifically, it delivers a radar cross-section reduction of − 20 dB m², a large apparent temperature modulation range (ΔT = 70 °C), and a low average IR emissivity of 0.35. Additionally, the optimal device demonstrates exceptional curved surface conformability, self-cleaning capability (contact angle ≈ 129°), and abrasion resistance (recovery time ≈ 5 s). This design strategy promotes the development of multispectral stealth technology and reinforces its applicability and durability in complex and hostile environments.

Highlights:
1 A multiscale hierarchical structure design, integrating wrinkled MXene radar-infrared shielding layer and flexible Fe₃O₄@C/PDMS microwave absorption layer
2 The assembled stealth devices realize a near-perfect stealth capability in both X-band (8-12 GHz) and long-wave infrared (8-14 µm) wavelength ranges.
3 The optimal device demonstrates exceptional curved surface conformability, self-cleaning capability (contact angle ≈ 129°), and abrasion resistance (recovery time ≈ 5 s).

Efficient and Stable Perovskite Solar Cells and Modules Enabled by Tailoring Additive Distribution According to the Film Growth Dynamics

2024-10-16T02:01:45+00:00

Gas quenching and vacuum quenching process are widely applied to accelerate solvent volatilization to induce nucleation of perovskites in blade-coating method. In this work, we found these two pre-crystallization processes lead to different order of crystallization dynamics within the perovskite thin film, resulting in the differences of additive distribution. We then tailor-designed an additive molecule named 1,3-bis(4-methoxyphenyl)thiourea to obtain films with fewer defects and holes at the buried interface, and prepared perovskite solar cells with a certified efficiency of 23.75%. Furthermore, this work also demonstrates an efficiency of 20.18% for the large-area perovskite solar module (PSM) with an aperture area of 60.84 cm². The PSM possesses remarkable continuous operation stability for maximum power point tracking of T₉₀ > 1000 h in ambient air.

Highlights:
1 Two pre-crystallization processes of gas quenching and vacuum quenching lead to different order of crystallization dynamics within the perovskite thin film, resulting in the differences of additive distribution.
2 A tailor designed 1,3-bis(4-methoxyphenyl)thiourea was utilized to improve the buried interface, leading to a certified efficiency of 23.75% for blade-coated perovskite solar cell.
3 The perovskite solar module (aperture area: 60.84 cm²) demonstrates an efficiency of 20.18% with excellent operational stability (maximum power point tracking of T90 > 1000 h).

Porous Organic Cage-Based Quasi-Solid-State Electrolyte with Cavity-Induced Anion-Trapping Effect for Long-Life Lithium Metal Batteries

2024-10-16T01:50:05+00:00

Porous organic cages (POCs) with permanent porosity and excellent host–guest property hold great potentials in regulating ion transport behavior, yet their feasibility as solid-state electrolytes has never been testified in a practical battery. Herein, we design and fabricate a quasi-solid-state electrolyte (QSSE) based on a POC to enable the stable operation of Li-metal batteries (LMBs). Benefiting from the ordered channels and cavity-induced anion-trapping effect of POC, the resulting POC-based QSSE exhibits a high Li⁺ transference number of 0.67 and a high ionic conductivity of 1.25 × 10⁻⁴ S cm⁻¹ with a low activation energy of 0.17 eV. These allow for homogeneous Li deposition and highly reversible Li plating/stripping for over 2000 h. As a proof of concept, the LMB assembled with POC-based QSSE demonstrates extremely stable cycling performance with 85% capacity retention after 1000 cycles. Therefore, our work demonstrates the practical applicability of POC as SSEs for LMBs and could be extended to other energy-storage systems, such as Na and K batteries.

Highlights:
1 A porous organic cage (POC)-based quasi-solid-state electrolyte (QSSE) with cavity-induced anion-trapping effect was rationally designed to enable the stable operation of Li-metal batteries.
2 The POC-based QSSE exhibits a high Li⁺ transference number of 0.67 and a high ionic conductivity of 1.25×10⁻⁴ S cm⁻¹ with a low activation energy of 0.17 eV.
3 The POC-based QSSE demonstrates a highly reversible Li plating/stripping cycling for 2000 h and superior Li||LFePO₄ cycling for thousands of cycles at room temperature.

An Unprecedented Efficiency with Approaching 21% Enabled by Additive-Assisted Layer-by-Layer Processing in Organic Solar Cells

2024-10-15T02:43:33+00:00

Recently published in Joule, Feng Liu and colleagues from Shanghai Jiaotong University reported a record-breaking 20.8% power conversion efficiency in organic solar cells (OSCs) with an interpenetrating fibril network active layer morphology, featuring a bulk p-i-n structure and proper vertical segregation achieved through additive-assisted layer-by-layer deposition. This optimized hierarchical gradient fibrillar morphology and optical management synergistically facilitates exciton diffusion, reduces recombination losses, and enhances light capture capability. This approach not only offers a solution to achieving high-efficiency devices but also demonstrates the potential for commercial applications of OSCs.

Highlights:
1 Additive-assisted layer-by-layer (LBL) deposition enables organic solar cells to achieve an unprecedented power conversion efficiency of 20.8%, the highest efficiency to date.
2 The gradient fibrillar morphology enabled by additive-assisted LBL processing promotes the formation of bulk p-i-n structure, improving exciton and carrier diffusion, and reducing recombination losses.
3 The wrinkle pattern morphology achieved by additive-assisted LBL processing is constructed to enhance the light capture capability.

MoS2 Lubricate-Toughened MXene/ANF Composites for Multifunctional Electromagnetic Interference Shielding

2024-10-15T02:27:52+00:00

The design and fabrication of high toughness electromagnetic interference (EMI) shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem. Ternary MXene/ANF (aramid nanofibers)–MoS₂ composite films with nacre-like layered structure here are fabricated after the introduction of MoS₂ into binary MXene/ANF composite system. The introduction of MoS₂ fulfills an impressive “kill three birds with one stone” improvement effect: lubrication toughening mechanical performance, reduction in secondary reflection pollution of electromagnetic wave, and improvement in the performance of photothermal conversion. After the introduction of MoS₂ into binary MXene/ANF (mass ratio of 50:50), the strain to failure and tensile strength increase from 22.1 1.7% and 105.7 6.4 MPa and to 25.8 0.7% and 167.3 9.1 MPa, respectively. The toughness elevates from 13.0 4.1 to 26.3 0.8 MJ m⁻³ (~ 102.3%) simultaneously. And the reflection shielding effectiveness (SE_R) of MXene/ANF (mass ratio of 50:50) decreases ~ 10.8%. EMI shielding effectiveness (EMI SE) elevates to 41.0 dB (8.2–12.4 GHz); After the introduction of MoS₂ into binary MXene/ANF (mass ratio of 60:40), the strain to failure increases from 18.3 1.9% to 28.1 0.7% (~ 53.5%), the SE_R decreases ~ 22.2%, and the corresponding EMI SE is 43.9 dB. The MoS₂ also leads to a more efficient photothermal conversion performance (~ 45 to ~ 55 °C). Additionally, MXene/ANF–MoS₂ composite films exhibit excellent electric heating performance, quick temperature elevation (15 s), excellent cycle stability (2, 2.5, and 3 V), and long-term stability (2520 s). Combining with excellent mechanical performance with high MXene content, electric heating performance, and photothermal conversion performance, EMI shielding ternary MXene/ANF–MoS₂ composite films could be applied in many industrial areas. This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.

Highlights:
1 The introduction of MoS₂ generates a “kill three birds with one stone” effect to the original binary MXene/ANF system: lubrication toughening mechanical performance; reduction in secondary reflection pollution of electromagnetic wave; and improvement in the performance of photothermal conversion.
2 After the introduction of MoS₂ into MXene/ANF (60:40), the strain and toughness were increased by 53.5% (from 18.3% to 28.1%) and 61.7% (from 8.9 to 14.5 MJ m⁻³), respectively. Fortunately, the SER decreases by 22.4%, and the photothermal conversion performance was increased by 22.2% from ~ 45 to ~ 55 °C.

High Fe-Loading Single-Atom Catalyst Boosts ROS Production by Density Effect for Efficient Antibacterial Therapy

2024-10-09T01:18:47+00:00

The current single-atom catalysts (SACs) for medicine still suffer from the limited active site density. Here, we develop a synthetic method capable of increasing both the metal loading and mass-specific activity of SACs by exchanging zinc with iron. The constructed iron SACs (h³-FNC) with a high metal loading of 6.27 wt% and an optimized adjacent Fe distance of ~ 4 Å exhibit excellent oxidase-like catalytic performance without significant activity decay after being stored for six months and promising antibacterial effects. Attractively, a “density effect” has been found at a high-enough metal doping amount, at which individual active sites become close enough to interact with each other and alter the electronic structure, resulting in significantly boosted intrinsic activity of single-atomic iron sites in h³-FNCs by 2.3 times compared to low- and medium-loading SACs. Consequently, the overall catalytic activity of h³-FNC is highly improved, with mass activity and metal mass-specific activity that are, respectively, 66 and 315 times higher than those of commercial Pt/C. In addition, h³-FNCs demonstrate efficiently enhanced capability in catalyzing oxygen reduction into superoxide anion (O₂·⁻) and glutathione (GSH) depletion. Both in vitro and in vivo assays demonstrate the superior antibacterial efficacy of h³-FNCs in promoting wound healing. This work presents an intriguing activity-enhancement effect in catalysts and exhibits impressive therapeutic efficacy in combating bacterial infections.

Highlights:
1 Fe single-atom catalysts (h³-FNCs) with high loading, high catalytic activity and high stability were synthesized via a method capable of increasing both the metal loading and mass-specific activity by exchanging zinc with iron.
2 The “density effect,” derived from the sufficiently high density of active sites, has been discovered for the first time, leading to a significant alteration in the intrinsic activity of single-atom metal sites.
3 The superior oxidase-like catalytic performance of h³-FNCs ensures highly effective bacterial eradication.

Aligned Ion Conduction Pathway of Polyrotaxane-Based Electrolyte with Dispersed Hydrophobic Chains for Solid-State Lithium–Oxygen Batteries

2024-10-03T06:39:01+00:00

A critical challenge hindering the practical application of lithium–oxygen batteries (LOBs) is the inevitable problems associated with liquid electrolytes, such as evaporation and safety problems. Our study addresses these problems by proposing a modified polyrotaxane (mPR)-based solid polymer electrolyte (SPE) design that simultaneously mitigates solvent-related problems and improves conductivity. mPR-SPE exhibits high ion conductivity (2.8 × 10⁻³ S cm⁻¹ at 25 °C) through aligned ion conduction pathways and provides electrode protection ability through hydrophobic chain dispersion. Integrating this mPR-SPE into solid-state LOBs resulted in stable potentials over 300 cycles. In situ Raman spectroscopy reveals the presence of an LiO₂ intermediate alongside Li₂O₂ during oxygen reactions. Ex situ X-ray diffraction confirm the ability of the SPE to hinder the permeation of oxygen and moisture, as demonstrated by the air permeability tests. The present study suggests that maintaining a low residual solvent while achieving high ionic conductivity is crucial for restricting the sub-reactions of solid-state LOBs.

Highlights:
1 Strategic materials design of polyrotaxane-based electrolytes was suggested by aligning the ion conduction pathways and dispersing hydrophobic chains for solid-state Li–O₂ batteries.
2 Owing to intentional design, solid-state Li–O₂ battery resulted in stable potential over 300 cycles at 25 °C.

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

2024-10-03T01:02:11+00:00

Hydrogel scaffolds have numerous potential applications in the tissue engineering field. However, tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties. Inspired by Chinese ramen, we propose a universal fabricating method (printing-P, training-T, cross-linking-C, PTC & PCT) for tough hydrogel scaffolds to fill this gap. First, 3D printing fabricates a hydrogel scaffold with desired structures (P). Then, the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance (T). Finally, the training results are fixed by photo-cross-linking processing (C). The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa (622-fold untreated) and have excellent biocompatibility. Furthermore, this scaffold possesses functional surface structures from nanometer to micron to millimeter, which can efficiently induce directional cell growth. Interestingly, this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt, and many hydrogels, such as gelatin and silk, could be improved with PTC or PCT strategies. Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers, blood vessels, and nerves within 4 weeks, prompting the rapid regeneration of large-volume muscle loss injuries.

Highlights:
1 We propose the novel concept of a tough hydrogel scaffold within the realm of tissue engineering. This scaffold combines exceptional strength (6.66 MPa), customization capabilities, and superior biocompatibility in a manner not previously achieved in existing research.
2 These tough hydrogel scaffolds possess functional surface structures and can effectively enhance cell-guided growth and prompt regeneration of muscle tissue in vivo.
3 This is a universal manufacturing method for tough hydrogel scaffolds in tissue engineering.

Locally Enhanced Flow and Electric Fields Through a Tip Effect for Efficient Flow-Electrode Capacitive Deionization

2024-10-02T08:21:25+00:00

Low-electrode capacitive deionization (FCDI) is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters. However, it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes, both restricted by the current collectors. Herein, a new tip-array current collector (designated as T-CC) was developed to replace the conventional planar current collectors, which intensifies both the charge transfer and ion transport significantly. The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy, which revealed the reduction of ion transport barrier, charge transport barrier and internal resistance. With the voltage increased from 1.0 to 1.5 and 2.0 V, the T-CC-based FCDI system (T-FCDI) exhibited average salt removal rates (ASRR) of 0.18, 0.50, and 0.89 μmol cm⁻² min⁻¹, respectively, which are 1.82, 2.65, and 2.48 folds higher than that of the conventional serpentine current collectors, and 1.48, 1.67, and 1.49 folds higher than that of the planar current collectors. Meanwhile, with the solid content in flow electrodes increased from 1 to 5 wt%, the ASRR for T-FCDI increased from 0.29 to 0.50 μmol cm⁻² min⁻¹, which are 1.70 and 1.67 folds higher than that of the planar current collectors. Additionally, a salt removal efficiency of 99.89% was achieved with T-FCDI and the charge efficiency remained above 95% after 24 h of operation, thus showing its superior long-term stability.

Highlights:
1 Steel tip arrays were used as current collectors to replace planar conductors.
2 Optimal flow and electric fields reduced barriers for electron and ion transport.
3 Desalination performance of flow-electrode capacitive deionization is enhanced by the tip-array current collectors.

An Efficient Boron Source Activation Strategy for the Low-Temperature Synthesis of Boron Nitride Nanotubes

2024-10-02T08:05:28+00:00

Lowering the synthesis temperature of boron nitride nanotubes (BNNTs) is crucial for their development. The primary reason for adopting a high temperature is to enable the effective activation of high-melting-point solid boron. In this study, we developed a novel approach for efficiently activating boron by introducing alkali metal compounds into the conventional MgO–B system. This approach can be adopted to form various low-melting-point AM–Mg–B–O growth systems. These growth systems have improved catalytic capability and reactivity even under low-temperature conditions, facilitating the synthesis of BNNTs at temperatures as low as 850 °C. In addition, molecular dynamics simulations based on density functional theory theoretically demonstrate that the systems maintain a liquid state at low temperatures and interact with N atoms to form BN chains. These findings offer novel insights into the design of boron activation and are expected to facilitate research on the low-temperature synthesis of BNNTs.

Highlights:
1 Developed more efficient boron activation strategies, while establishing various low-melting growth systems.
2 The preparation temperature of boron nitride nanotubes has been reduced to 850 °C.

Defects-Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

2024-10-02T07:45:24+00:00

Multiple Tin Compounds Modified Carbon Fibers to Construct Heterogeneous Interfaces for Corrosion Prevention and Electromagnetic Wave Absorption

2024-10-02T07:34:59+00:00

Currently, the demand for electromagnetic wave (EMW) absorbing materials with specific functions and capable of withstanding harsh environments is becoming increasingly urgent. Multi-component interface engineering is considered an effective means to achieve high-efficiency EMW absorption. However, interface modulation engineering has not been fully discussed and has great potential in the field of EMW absorption. In this study, multi-component tin compound fiber composites based on carbon fiber (CF) substrate were prepared by electrospinning, hydrothermal synthesis, and high-temperature thermal reduction. By utilizing the different properties of different substances, rich heterogeneous interfaces are constructed. This effectively promotes charge transfer and enhances interfacial polarization and conduction loss. The prepared SnS/SnS₂/SnO₂/CF composites with abundant heterogeneous interfaces have and exhibit excellent EMW absorption properties at a loading of 50 wt% in epoxy resin. The minimum reflection loss (RL) is − 46.74 dB and the maximum effective absorption bandwidth is 5.28 GHz. Moreover, SnS/SnS₂/SnO₂/CF epoxy composite coatings exhibited long-term corrosion resistance on Q235 steel surfaces. Therefore, this study provides an effective strategy for the design of high-efficiency EMW absorbing materials in complex and harsh environments.

Highlights:
1 Excellent impedance matching through component modulation engineering.
2 Rich heterogeneous interfaces are constructed to realize excellent electromagnetic wave (EMW) absorption performance.
3 Long-term corrosion protection and excellent EMW absorption properties.

Constructing Donor–Acceptor-Linked COFs Electrolytes to Regulate Electron Density and Accelerate the Li+ Migration in Quasi-Solid-State Battery

2024-10-02T05:40:20+00:00

Regulation the electronic density of solid-state electrolyte by donor–acceptor (D–A) system can achieve highly-selective Li⁺ transportation and conduction in solid-state Li metal batteries. This study reports a high-performance solid-state electrolyte thorough D–A-linked covalent organic frameworks (COFs) based on intramolecular charge transfer interactions. Unlike other reported COF-based solid-state electrolyte, the developed concept with D–A-linked COFs not only achieves electronic modulation to promote highly-selective Li⁺ migration and inhibit Li dendrite, but also offers a crucial opportunity to understand the role of electronic density in solid-state Li metal batteries. The introduced strong electronegativity F-based ligand in COF electrolyte results in highly-selective Li⁺ (transference number 0.83), high ionic conductivity (6.7 × 10^–4 S cm⁻¹), excellent cyclic ability (1000 h) in Li metal symmetric cell and high-capacity retention in Li/LiFePO₄ cell (90.8% for 300 cycles at 5C) than substituted C- and N-based ligands. This is ascribed to outstanding D–A interaction between donor porphyrin and acceptor F atoms, which effectively expedites electron transferring from porphyrin to F-based ligand and enhances Li⁺ kinetics. Consequently, we anticipate that this work creates insight into the strategy for accelerating Li⁺ conduction in high-performance solid-state Li metal batteries through D–A system.

Highlights:
1 Donor–acceptor-linked covalent organic framework (COF)-based electrolyte can not only fulfill highly-selective Li⁺ conduction, but also offer a crucial opportunity to understand the role of electronic density in quasi-solid-state Li metal batteries.
2 Donor–acceptor-linked COF electrolyte results in Li+ transference number 0.83, high ionic conductivity 6.7 × 10^–4 S cm⁻¹ and excellent cyclic ability in Li metal batteries.
3 In situ characterizations, density functional theory calculation and time-of-flight secondary ion mass spectrometry are adopted to expound the mechanism of the rapid migration of Li⁺ in the “donor–acceptor” electrolyte system.

Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption

2024-10-01T06:49:08+00:00

Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption (EMWA) materials. However, the relationship between configuration and electromagnetic (EM) loss mechanism has remained elusive. Herein, drawing inspiration from the DNA transcription process, we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability. Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N₄–C configuration, along with cross polarization generated by the helical structure, endow the helical converters with enhanced EM loss. As a result, HMC-8 demonstrates outstanding EMWA performance, achieving a minimum reflection loss of −63.13 dB at an ultralow thickness of 1.29 mm. Through precise tuning of the graphite domain size, HMC-7 achieves an effective absorption bandwidth (EAB) of 6.08 GHz at 2.02 mm thickness. Furthermore, constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm, with the maximum radar cross section reduction value reaching 36.4 dB m². This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA, thus contributing to the development of EMWA mechanisms and applications.

Highlights:
1 The energy conversion mechanism is thoroughly analyzed, with a detailed quantitative characterization of the dissipation capacities of polarization, conduction, and magnetic loss.
2 Inspired by DNA transcription, atom and geometry configurations co-modulating multi-scale helical converters achieve the RLmin of −63.13 dB at 1.29 mm, and the maximum RCS reduction value reach 36.4 dB m².
3 Orbital coupling, spin and cross polarization synergize to realize a 6.08 GHz EAB, further expanding to ultrabroad electromagnetic wave absorption of 12.16 GHz through metamaterial design.

Spontaneous Orientation Polarization of Anisotropic Equivalent Dipoles Harnessed by Entropy Engineering for Ultra-Thin Electromagnetic Wave Absorber

2024-10-01T06:39:23+00:00

The synthesis of carbon supporter/nanoscale high-entropy alloys (HEAs) electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes. Electron migration modes within HEAs as manipulated by the electronegativity, valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles. Herein, enlightened by skin-like effect, a reformative carbothermal shock method using carbonized cellulose paper (CCP) as carbon supporter is used to preserve the oxygen-containing functional groups (O·) of carbonized cellulose fibers (CCF). Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·. Meanwhile, the electron migration mode of switchable electron-rich sites promotes the orientation polarization of anisotropic equivalent dipoles. By virtue of the reinforcement strategy, CCP/HEAs composite prepared by 35% molar ratio of Mn element (CCP/HEAs-Mn_2.15) achieves efficient electromagnetic wave (EMW) absorption of − 51.35 dB at an ultra-thin thickness of 1.03 mm. The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations, which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices (e.g., ultra-wideband bandpass filter).

Highlights:
1 The strengthening mechanism of spontaneous orientation polarization of anisotropic equivalent dipoles within high-entropy alloys (HEAs) is proposed for enhancing dielectric attenuation of HEAs.
2 The source of carbon supporter is expanded to the biomass category, which can construct the shell-core heterointerfaces with HEAs by means of a reformative carbothermal shock method.
3 The sample carbonized cellulose paper/HEAs-Mn_2.15 achieves efficient electromagnetic wave absorption of -51.35 dB at an ultra-thin thickness of 1.03 mm.
4 This work combines theoretical calculations and electromagnetic simulations to propose feasible strategies for the design and application of electromagnetic functional devices such as ultra-wideband bandpass filter.

Molecule-Level Multiscale Design of Nonflammable Gel Polymer Electrolyte to Build Stable SEI/CEI for Lithium Metal Battery

2024-10-01T06:22:53+00:00

The risk of flammability is an unavoidable issue for gel polymer electrolytes (GPEs). Usually, flame-retardant solvents are necessary to be used, but most of them would react with anode/cathode easily and cause serious interfacial instability, which is a big challenge for design and application of nonflammable GPEs. Here, a nonflammable GPE (SGPE) is developed by in situ polymerizing trifluoroethyl methacrylate (TFMA) monomers with flame-retardant triethyl phosphate (TEP) solvents and LiTFSI–LiDFOB dual lithium salts. TEP is strongly anchored to PTFMA matrix via polarity interaction between -P = O and -CH₂CF₃. It reduces free TEP molecules, which obviously mitigates interfacial reactions, and enhances flame-retardant performance of TEP surprisingly. Anchored TEP molecules are also inhibited in solvation of Li⁺, leading to anion-dominated solvation sheath, which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers. Such coordination structure changes Li⁺ transport from sluggish vehicular to fast structural transport, raising ionic conductivity to 1.03 mS cm⁻¹ and transfer number to 0.41 at 30 °C. The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm⁻², and 4.2 V LiCoO₂|SGPE|Li battery delivers high average specific capacity > 120 mAh g⁻¹ over 200 cycles. This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.

Highlights:
1 Nonflammable gel polymer electrolyte (SGPE) is developed by in situ polymerizing trifluoroethyl methacrylate (TFMA) monomers with flame-retardant triethyl phosphate (TEP) solvents and LiTFSI–LiDFOB dual lithium salts.
2 Molecular polarity interaction between TEP and PTFMA mitigates interfacial reactions and changes the solvation of Li⁺.
3 SGPE forms stable inorganic-rich solid electrolyte interface/cathode electrolyte interface layer, exhibiting well compatibility with Li anode and LiCoO₂-type high-voltage cathode.

Bioinspired Passive Tactile Sensors Enabled by Reversible Polarization of Conjugated Polymers

2024-10-01T06:05:15+00:00

Tactile perception plays a vital role for the human body and is also highly desired for smart prosthesis and advanced robots. Compared to active sensing devices, passive piezoelectric and triboelectric tactile sensors consume less power, but lack the capability to resolve static stimuli. Here, we address this issue by utilizing the unique polarization chemistry of conjugated polymers for the first time and propose a new type of bioinspired, passive, and bio-friendly tactile sensors for resolving both static and dynamic stimuli. Specifically, to emulate the polarization process of natural sensory cells, conjugated polymers (including poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), polyaniline, or polypyrrole) are controllably polarized into two opposite states to create artificial potential differences. The controllable and reversible polarization process of the conjugated polymers is fully in situ characterized. Then, a micro-structured ionic electrolyte is employed to imitate the natural ion channels and to encode external touch stimulations into the variation in potential difference outputs. Compared with the currently existing tactile sensing devices, the developed tactile sensors feature distinct characteristics including fully organic composition, high sensitivity (up to 773 mV N⁻¹), ultralow power consumption (nW), as well as superior bio-friendliness. As demonstrations, both single point tactile perception (surface texture perception and material property perception) and two-dimensional tactile recognitions (shape or profile perception) with high accuracy are successfully realized using self-defined machine learning algorithms. This tactile sensing concept innovation based on the polarization chemistry of conjugated polymers opens up a new path to create robotic tactile sensors and prosthetic electronic skins.

Highlights:
1 Fully organic and passive tactile sensors are developed via mimicking the sensing behavior of natural sensory cells.
2 Controllable polarizability of conjugated polymers is adopted for the first time to construct passive tactile sensors.
3 Machine learning-assisted surface texture detection, material property recognition, as well as shape/profile perception are realized with the tactile sensors.

“Zero-Strain” NiNb2O6 Fibers for All-Climate Lithium Storage

2024-10-01T05:51:37+00:00

Niobates are promising all-climate Li⁺-storage anode material due to their fast charge transport, large specific capacities, and resistance to electrolyte reaction. However, their moderate unit-cell-volume expansion (generally 5%–10%) during Li⁺ storage causes unsatisfactory long-term cyclability. Here, “zero-strain” NiNb₂O₆ fibers are explored as a new anode material with comprehensively good electrochemical properties. During Li⁺ storage, the expansion of electrochemical inactive NiO₆ octahedra almost fully offsets the shrinkage of active NbO₆ octahedra through reversible O movement. Such superior volume-accommodation capability of the NiO₆ layers guarantees the “zero-strain” behavior of NiNb₂O₆ in a broad temperature range (0.53%//0.51%//0.74% at 25// − 10//60 °C), leading to the excellent cyclability of the NiNb₂O₆ fibers (92.8%//99.2% // 91.1% capacity retention after 1000//2000//1000 cycles at 10C and 25// − 10//60 °C). This NiNb₂O₆ material further exhibits a large reversible capacity (300//184//318 mAh g⁻¹ at 0.1C and 25// − 10//60 °C) and outstanding rate performance (10 to 0.5C capacity percentage of 64.3%//50.0%//65.4% at 25// − 10//60 °C). Therefore, the NiNb₂O₆ fibers are especially suitable for large-capacity, fast-charging, long-life, and all-climate lithium-ion batteries.

Highlights:
1 “Zero-strain” NiNb₂O₆ fibers with nanosized primary particles are explored as an all-climate anode material with comprehensively good Li⁺-storage properties.
2 The almost completely opposite volume changes of electrochemical inactive NiO₆ octahedra and active NbO₆ octahedra are achieved through reversible O movement, leading to the “zero-strain” behavior of NiNb₂O₆ with minor unit-cell-volume change and excellent cyclability in a broad temperature range.
3 The gained insight can provide guide for the exploration of high-performance energy-storage materials working at harsh temperatures.

Smart Cellulose-Based Janus Fabrics with Switchable Liquid Transportation for Personal Moisture and Thermal Management

2024-10-01T05:35:21+00:00

The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort. However, the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge. Herein, a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat. The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel. Subsequently, hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient. The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side, and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40 °C. This smart fabric can quickly dissipate heat at high temperatures, while at low temperatures, it can slow down the heat dissipation rate and prevent the human from becoming too cold. In addition, the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side. This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations.

Highlights:
1 A smart all-cellulose Janus fabric was designed for personal moisture/thermal management.
2 The fabric can dynamically and continuously control the liquid transportation time in response to the temperature.
3 The fabric can accelerate the heat dissipation rate at high temperatures, while slow it down at low temperatures.

Alternative Strategy for Development of Dielectric Calcium Copper Titanate-Based Electrolytes for Low-Temperature Solid Oxide Fuel Cells

2024-10-01T05:21:42+00:00

The development of low-temperature solid oxide fuel cells (LT-SOFCs) is of significant importance for realizing the widespread application of SOFCs. This has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of SOFCs. In this context, for the first time, a dielectric material, CaCu₃Ti₄O₁₂ (CCTO) is designed for LT-SOFCs electrolyte application in this study. Both individual CCTO and its heterostructure materials with a p-type Ni_0.8Co_0.15Al_0.05LiO_2−δ (NCAL) semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550 °C. The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm⁻² and an open-circuit voltage (OCV) of 0.95 V at 550 °C, while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm⁻² along with a higher OCV over 1.0 V, which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting risk. It is found that these promising outcomes are due to the interplay of the dielectric material, its structure, and overall properties that led to improve electrochemical mechanism in CCTO–NCAL. Furthermore, density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–NCAL. Our study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.

Highlights:
1 Dielectric CaCu₃Ti₄O₁₂ (CCTO) was used as electrolyte in low-temperature solid oxide fuel cells for the first time.
2 A new heterostructure electrolyte was designed based on CCTO and Ni_0.8Co_0.15Al_0.05LiO_2−δ (NCAL). Promising ionic conductivity and high fuel cell performance were achieved
3 CCTO–NCAL realized an electrolyte function due to its good dielectric property and a heterojunction effect.

Ultra-Transparent and Multifunctional IZVO Mesh Electrodes for Next-Generation Flexible Optoelectronics

2024-10-01T05:13:29+00:00

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic devices. Furthermore, they are crucial for applications in the fields of energy, display, healthcare, and soft robotics. Conducting meshes represent a promising alternative to traditional, brittle, metal oxide conductors due to their high electrical conductivity, optical transparency, and enhanced mechanical flexibility. In this paper, we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using self-cracking-assisted templates. Using this method, we produced an electrode with ultra-transparency (97.39%), high conductance (R_s = 21.24 Ω sq⁻¹), elevated work function (5.16 eV), and good mechanical stability. We also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics, organic light-emitting diodes, and flexible transparent memristor devices for neuromorphic computing, resulting in exceptional device performance. In addition, the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility, rendering them a promising option for application in flexible optoelectronics.

Highlights:
1 Ultra-transparent vanadium-doped indium zinc oxide mesh (mIZVO) electrodes are fabricated using a self-cracking template.
2 Fabricated electrodes are employed to realize flexible organic solar cell (OSC), organic light-emitting diode (OLED), and memristor devices. OSC exhibits 14.38% power conversion efficiency and OLED achieves 18.06% external quantum efficiency with mIZVO electrode.
3 Flexible-transparent memristor based on mIZVO mimics various synaptic functions.

Boosting Oxygen Evolution Reaction Performance on NiFe-Based Catalysts Through d-Orbital Hybridization

2024-10-01T00:48:12+00:00

Anion-exchange membrane water electrolyzers (AEMWEs) for green hydrogen production have received intensive attention due to their feasibility of using earth-abundant NiFe-based catalysts. By introducing a third metal into NiFe-based catalysts to construct asymmetrical M-NiFe units, the d-orbital and electronic structures can be adjusted, which is an important strategy to achieve sufficient oxygen evolution reaction (OER) performance in AEMWEs. Herein, the ternary NiFeM (M: La, Mo) catalysts featured with distinct M-NiFe units and varying d-orbitals are reported in this work. Experimental and theoretical calculation results reveal that the doping of La leads to optimized hybridization between d orbital in NiFeM and 2p in oxygen, resulting in enhanced adsorption strength of oxygen intermediates, and reduced rate-determining step energy barrier, which is responsible for the enhanced OER performance. More critically, the obtained NiFeLa catalyst only requires 1.58 V to reach 1 A cm⁻² in an anion exchange membrane electrolyzer and demonstrates excellent long-term stability of up to 600 h.

Highlights:
1 The NiFeLa catalyst with 3d-5d orbital coupling exhibits remarkable oxygen evolution reaction (OER) activity and stability, enabling an anion-exchange membrane water electrolyzers device to achieve a cell voltage of only 1.58 V at 1 A cm⁻² as well as long-term stability over 600 h.
2 The introduction of La disrupts the symmetry of Ni-Fe units and optimize d band center, which affects the d-p orbital hybridization between the metal sites on the surface of the catalyst and oxygen-containing intermediates during the OER process.
3 The 5d-introduced NiFeLa has enhanced adsorption strength of oxygen intermediates, which can reduce the rate-determining step energy barrier and prevent catalyst dissolution.

Tailoring Light–Matter Interactions in Overcoupled Resonator for Biomolecule Recognition and Detection

2024-09-30T07:42:32+00:00

Plasmonic nanoantennas provide unique opportunities for precise control of light–matter coupling in surface-enhanced infrared absorption (SEIRA) spectroscopy, but most of the resonant systems realized so far suffer from the obstacles of low sensitivity, narrow bandwidth, and asymmetric Fano resonance perturbations. Here, we demonstrated an overcoupled resonator with a high plasmon-molecule coupling coefficient (μ) (OC-Hμ resonator) by precisely controlling the radiation loss channel, the resonator-oscillator coupling channel, and the frequency detuning channel. We observed a strong dependence of the sensing performance on the coupling state, and demonstrated that OC-Hμ resonator has excellent sensing properties of ultra-sensitive (7.25% nm⁻¹), ultra-broadband (3–10 μm), and immune asymmetric Fano lineshapes. These characteristics represent a breakthrough in SEIRA technology and lay the foundation for specific recognition of biomolecules, trace detection, and protein secondary structure analysis using a single array (array size is 100 × 100 µm²). In addition, with the assistance of machine learning, mixture classification, concentration prediction and spectral reconstruction were achieved with the highest accuracy of 100%. Finally, we demonstrated the potential of OC-Hμ resonator for SARS-CoV-2 detection. These findings will promote the wider application of SEIRA technology, while providing new ideas for other enhanced spectroscopy technologies, quantum photonics and studying light–matter interactions.

Highlights:
1 Proposed a new paradigm for nanoantenna design using coupled-mode theory.
2 Designed an OC-Hµ resonator with excellent sensing performance.
3 Using OC-Hµ resonators for biomolecule recognition and detection.

Crystallization Modulation and Holistic Passivation Enables Efficient Two-Terminal Perovskite/CuIn(Ga)Se2 Tandem Solar Cells

2024-09-25T06:20:35+00:00

Two-terminal (2-T) perovskite (PVK)/CuIn(Ga)Se₂ (CIGS) tandem solar cells (TSCs) have been considered as an ideal tandem cell because of their best bandgap matching regarding to Shockley–Queisser (S–Q) limits. However, the nature of the irregular rough morphology of commercial CIGS prevents people from improving tandem device performances. In this paper, D-homoserine lactone hydrochloride is proven to improve coverage of PVK materials on irregular rough CIGS surfaces and also passivate bulk defects by modulating the growth of PVK crystals. In addition, the minority carriers near the PVK/C60 interface and the incompletely passivated trap states caused interface recombination. A surface reconstruction with 2-thiopheneethylammonium iodide and N,N-dimethylformamide assisted passivates the defect sites located at the surface and grain boundaries. Meanwhile, LiF is used to create this field effect, repelling hole carriers away from the PVK and C60 interface and thus reducing recombination. As a result, a 2-T PVK/CIGS tandem yielded a power conversion efficiency of 24.6% (0.16 cm²), one of the highest results for 2-T PVK/CIGS TSCs to our knowledge. This validation underscores the potential of our methodology in achieving superior performance in PVK/CIGS tandem solar cells.

Highlights:
1 Integrating perovskite solar cells onto irregular rough CuIn(Ga)Se₂ (CIGS) surfaces remains a challenge; new strategy was explored to develop monolithic perovskite/CIGS tandem solar cell by manipulating the crystallization of perovskite.
2 Surface reconstruction and field-effect passivation are developed synergistically to issue complex interface relationship between perovskite and C60.
3 The champion power conversion efficiency （PCE） of 24.6% realized, providing significant commercial opportunities for all thin-film-based perovskite/CIGS tandem cells.

Low-Temperature Oxidation Induced Phase Evolution with Gradient Magnetic Heterointerfaces for Superior Electromagnetic Wave Absorption

2024-09-25T06:06:08+00:00

Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching, adjusting dielectric/magnetic resonance and promoting electromagnetic (EM) wave absorption, but still exist a significant challenging in regulating local phase evolution. Herein, accordion-shaped Co/Co₃O₄@N-doped carbon nanosheets (Co/Co₃O₄@NC) with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and low-temperature oxidation process. The results indicate that the surface epitaxial growth of crystal Co₃O₄ domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components, which are beneficial for optimizing impedance matching and interfacial polarization. Moreover, gradient magnetic heterointerfaces simultaneously realize magnetic coupling, and long-range magnetic diffraction. Specifically, the synthesized Co/Co₃O₄@NC absorbents display the strong electromagnetic wave attenuation capability of − 53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz, both are superior to those of single magnetic domains embedded in carbon matrix. This design concept provides us an inspiration in optimizing interfacial polarization, regulating magnetic coupling and promoting electromagnetic wave absorption.

Highlights:
1 Co/Co₃O₄@NC nanosheets with gradient magnetic heterointerfaces have been fabricated by the high-temperature carbonization/low-temperature oxidation processes.
2 Experimental and theoretical simulation results indicate that magnetic heterointerfaces engineering is beneficial for optimizing impedance matching and promoting electromagnetic wave absorption.
3 Gradient magnetic heterointerfaces with magnetic-heteroatomic components realize the adjustment of interfacial polarization, magnetic coupling, and long-range magnetic diffraction.

Catalyst–Support Interaction in Polyaniline-Supported Ni3Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn-Air Batteries

2024-09-25T05:48:03+00:00

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction (OER). Here we modulate the catalyst–support interaction in polyaniline-supported Ni₃Fe oxide (Ni₃Fe oxide/PANI) with a robust hetero-interface, which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm⁻² and specific activity of 2.08 mA cm_ECSA⁻² at overpotential of 300 mV, 3.84-fold that of Ni₃Fe oxide. It is revealed that the catalyst–support interaction between Ni₃Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond, thus promoting the charge and mass transfer on Ni₃Fe oxide. Considering the excellent activity and stability, rechargeable Zn-air batteries with optimum Ni₃Fe oxide/PANI are assembled, delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm⁻². The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Highlights:
1 Ni₃Fe oxide, with an average size of 3.5 ± 1.5 nm, was successfully deposited onto polyaniline (PANI) support through a solvothermal strategy followed by calcination.
2 The catalyst–support interaction between Ni₃Fe oxide and PANI can enhance the Ni-O covalency via the interfacial Ni-N bond.
3 Ni₃Fe oxide/PANI-assembled Zn-air batteries achieve superior cycling life for over 400 h at 10 mA cm⁻² and a low charge potential of around 1.95 V.

Photo-Energized MoS2/CNT Cathode for High-Performance Li–CO2 Batteries in a Wide-Temperature Range

2024-09-25T05:32:08+00:00

Li–CO₂ batteries are considered promising energy storage systems in extreme environments such as Mars; however, severe performance degradation will occur at a subzero temperature owning to the sluggish reaction kinetics. Herein, a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li–CO₂ battery was achieved with a binder-free MoS₂/carbon nanotube (CNT) photo-electrode as cathode. The unique layered structure and excellent photoelectric properties of MoS₂ facilitate the abundant generation and rapid transfer of photo-excited carriers, which accelerate the CO₂ reduction and Li₂CO₃ decomposition upon illumination. The illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V, attaining superior energy efficiency of 90.2% and excellent cycling stability of over 120 cycles. Even at an extremely low temperature of − 30 °C, the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS₂/CNT cathode. This work demonstrates the promising potential of the photo-energized wide working temperature range Li–CO₂ battery in addressing the obstacle of charge overpotential and energy efficiency.

Highlights:
1 The unique layered structure and excellent photoelectric properties of MoS₂ facilitate the abundant generation and rapid transfer of photo-excited carriers, which accelerate the CO₂ reduction and Li₂CO₃ decomposition upon illumination.
2 MoS₂-based photo-energized Li–CO₂ battery displays ultra-low charge voltage of 3.27 V, high energy efficiency of 90.2%, superior cycling stability after 120 cycles and high rate capability.
3 The low-temperature Li–CO₂ battery achieves an ultra-low charge voltage of 3.4 V at –30 °C with a round-trip efficiency of 86.6%.

Advances in Anion Chemistry in the Electrolyte Design for Better Lithium Batteries

2025-02-18T02:00:27+00:00

Electrolytes are crucial components in electrochemical energy storage devices, sparking considerable research interest. However, the significance of anions in the electrolytes is often underestimated. In fact, the anions have significant impacts on the performance and stability of lithium batteries. Therefore, comprehensively understanding anion chemistry in electrolytes is of crucial importance. Herein, in-depth comprehension of anion chemistry and its positive effects on the interface, solvation structure of Li-ions, as well as the electrochemical performance of the batteries have been emphasized and summarized. This review aims to present a full scope of anion chemistry and furnish systematic cognition for the rational design of advanced electrolytes for better lithium batteries with high energy density, lifespan, and safety. Furthermore, insightful analysis and perspectives based on the current research are proposed. We hope that this review sheds light on new perspectives on understanding anion chemistry in electrolytes.

Highlights:
1 The impact of anions on the interface is summarized, including forming a solid electrolyte interphase (SEI), repairing the damaged SEI, and modulate electric double layer.
2 The influence of anions on the solvation structure is presented, including enhancing desolvation process of the Li-ions and the antioxidant property of the electrolyte.
3 This review also emphasizes the important role of anions in enhancing battery safety through their flame-retardant properties, as well as their impact on energy density and power density by altering reaction pathways and accelerating reactions.

Recent Advances of Electrocatalysts and Electrodes for Direct Formic Acid Fuel Cells: from Nano to Meter Scale Challenges

2025-02-18T01:38:18+00:00

Direct formic acid fuel cells are promising energy devices with advantages of low working temperature and high safety in fuel storage and transport. They have been expected to be a future power source for portable electronic devices. The technology has been developed rapidly to overcome the high cost and low power performance that hinder its practical application, which mainly originated from the slow reaction kinetics of the formic acid oxidation and complex mass transfer within the fuel cell electrodes. Here, we provide a comprehensive review of the progress around this technology, in particular for addressing multiscale challenges from catalytic mechanism understanding at the atomic scale, to catalyst design at the nanoscale, electrode structure at the micro scale and design at the millimeter scale, and finally to device fabrication at the meter scale. The gap between the highly active electrocatalysts and the poor electrode performance in practical devices is highlighted. Finally, perspectives and opportunities are proposed to potentially bridge this gap for further development of this technology.

Highlights:
1 Comprehensive review of the progress in direct formic acid fuel cells from catalytic mechanisms to catalyst design, and to the electrode/device fabrication.
2 The gap between highly active formic acid oxidation catalysts and unsatisfactory device performance is highlighted.
3 Perspectives for catalyst and electrode design are discussed.

Fast-Developing Dynamic Radiative Thermal Management: Full-Scale Fundamentals, Switching Methods, Applications, and Challenges

2025-02-18T01:04:49+00:00

Rapid population growth in recent decades has intensified both the global energy crisis and the challenges posed by climate change, including global warming. Currently, the increased frequency of extreme weather events and large fluctuations in ambient temperature disrupt thermal comfort and negatively impact health, driving a growing dependence on cooling and heating energy sources. Consequently, efficient thermal management has become a central focus of energy research. Traditional thermal management systems consume substantial energy, further contributing to greenhouse gas emissions. In contrast, emergent radiant thermal management technologies that rely on renewable energy have been proposed as sustainable alternatives. However, achieving year-round thermal management without additional energy input remains a formidable challenge. Recently, dynamic radiative thermal management technologies have emerged as the most promising solution, offering the potential for energy-efficient adaptation across seasonal variations. This review systematically presents recent advancements in dynamic radiative thermal management, covering fundamental principles, switching mechanisms, primary materials, and application areas. Additionally, the key challenges hindering the broader adoption of dynamic radiative thermal management technologies are discussed. By highlighting their transformative potential, this review provides insights into the design and industrial scalability of these innovations, with the ultimate aim of promoting renewable energy integration in thermal management applications.

Highlights:
1 This review comprehensively summarizes the current state-of-the-art in dynamic radiative thermal management technology.
2 In-depth discussion of the basic principles of dynamic radiative thermal management technology, design strategies, and a list of related applications are presented.
3 An in-depth look at the challenges facing dynamic radiative thermal management technology, providing potential solutions for the future direction of the field.

Structural Mechanisms of Quasi-2D Perovskites for Next-Generation Photovoltaics

2025-02-11T04:49:03+00:00

Quasi-two-dimensional (2D) perovskite embodies characteristics of both three-dimensional (3D) and 2D perovskites, achieving the superior external environment stability structure of 2D perovskites alongside the high efficiency of 3D perovskites. This effect is realized through critical structural modifications in device fabrication. Typically, perovskites have an octahedral structure, generally ABX₃, where an organic ammonium cation (A') participates in forming the perovskite structure, with A'_(n) (n = 1 or 2) sandwiched between A_(n-1)B_(n)X_(3n+1) perovskite layers. Depending on whether A' is a monovalent or divalent cation, 2D perovskites are classified into Ruddlesden-Popper perovskite or Dion-Jacobson perovskite, each generating different structures. Although each structure achieves similar effects, they incorporate distinct mechanisms in their formation. And according to these different structures, various properties appear, and additive and optimizing methods to increase the efficiency of 3D perovskites also exist in 2D perovskites. In this review, scientific understanding and engineering perspectives of the quasi-2D perovskite is investigated, and the optimal structure quasi-2D and the device optimization is also discussed to provide the insight in the field.

Highlights:
1 This review highlights the structural advantages and challenges of qausi-2D perovskite.
2 Beyond these structural adaptations, unique additive methods specific to quasi-2D perovskites are suggested, alongside future directions for further improvement.
3 Material and device analysis using Ruddlesden–Popper, Dion–Jacobson, and alternating cation phases are discussed.

Artificial Intelligence-Powered Materials Science

2025-02-11T04:02:20+00:00

The advancement of materials has played a pivotal role in the advancement of human civilization, and the emergence of artificial intelligence (AI)-empowered materials science heralds a new era with substantial potential to tackle the escalating challenges related to energy, environment, and biomedical concerns in a sustainable manner. The exploration and development of sustainable materials are poised to assume a critical role in attaining technologically advanced solutions that are environmentally friendly, energy-efficient, and conducive to human well-being. This review provides a comprehensive overview of the current scholarly progress in artificial intelligence-powered materials science and its cutting-edge applications. We anticipate that AI technology will be extensively utilized in material research and development, thereby expediting the growth and implementation of novel materials. AI will serve as a catalyst for materials innovation, and in turn, advancements in materials innovation will further enhance the capabilities of AI and AI-powered materials science. Through the synergistic collaboration between AI and materials science, we stand to realize a future propelled by advanced AI-powered materials.

Highlights:
1 A detailed exploration is provided of how artificial intelligence (AI) and machine learning techniques are applied across various aspects of materials science.
2 Major challenges in AI-driven materials science are evaluated.
3 Novel case studies are incorporated, demonstrating their impact on accelerating material development and discovery.

Microneedle-Based Approaches for Skin Disease Treatment

2025-02-11T03:27:15+00:00

The use of microneedles (MNs) has been established as an effective transdermal drug delivery strategy that has been extensively deployed for treating various diseases, including skin diseases. MNs can surpass the constraints of conventional drug delivery methods by their superior safety and efficacy through precise targeting, while simultaneously enabling painless delivery. Currently, MNs are increasingly used as carriers for drug delivery, with the loading of insoluble drugs to improve their treatment efficiency or combining with bioactive substances for the construction of an efficient drug delivery system to maximize the effects of bioactive substances. The methods used for preparation MNs are diverse, enabling them to meet the requirements of most applications. The emergence of MNs has addressed the shortcomings associated with insoluble drugs, expanded the applications of bioactive substances, and improved their use in clinical practice. This review summarizes current information on the application of MNs in a variety of skin diseases, such as psoriasis, vitiligo, alopecia, hypertrophic scarring, atopic dermatitis, melanoma, acne, and skin infections. The current clinical applications and future opportunities for MNs in the treatment of skin diseases are also discussed. Despite substantial progress in the clinical application of MNs as delivery vectors, issues such as low drug loading and poor mechanical strength during MNs preparation remain the main challenges. Therefore, clinical implementation of MNs-based therapies remains limited, highlighting key opportunities for future research.

Highlights:
1 Microneedles (MNs) are used extensively for treating skin diseases due to their capability to provide less-invasive targeted drug delivery.
2 Intelligent MNs can be fabricated from biocompatible materials with specialized properties, thereby providing improved treatment efficacy.
3 Currently, there are limitations in the clinical application of MNs, highlighting the significance of further investigation to facilitate the translation of this innovative technology into patient treatment contexts.

Functionalized Separators Boosting Electrochemical Performances for Lithium Batteries

2025-02-07T07:24:41+00:00

The growing demands for energy storage systems, electric vehicles, and portable electronics have significantly pushed forward the need for safe and reliable lithium batteries. It is essential to design functional separators with improved mechanical and electrochemical characteristics. This review covers the improved mechanical and electrochemical performances as well as the advancements made in the design of separators utilizing a variety of techniques. In terms of electrolyte wettability and adhesion of the coating materials, we provide an overview of the current status of research on coated separators, in situ modified separators, and grafting modified separators, and elaborate additional performance parameters of interest. The characteristics of inorganics coated separators, organic framework coated separators and inorganic–organic coated separators from different fabrication methods are compared. Future directions regarding new modified materials, manufacturing process, quantitative analysis of adhesion and so on are proposed toward next-generation advanced lithium batteries.

Highlights:
1 The commonly used modification methods for separator of lithium batteries are summarized, which include surface coating, in situ modification and grafting modification.
2 The adhesion of coating materials with the separators and wettability of the modified separators prepared from the three methods are compared.
3 The challenges and future directions of separator modification are provided.

Advanced Bismuth-Based Anode Materials for Efficient Potassium Storage: Structural Features, Storage Mechanisms and Modification Strategies

2025-02-07T07:03:27+00:00

Potassium-ion batteries (PIBs) are considered as a promising energy storage system owing to its abundant potassium resources. As an important part of the battery composition, anode materials play a vital role in the future development of PIBs. Bismuth-based anode materials demonstrate great potential for storing potassium ions (K⁺) due to their layered structure, high theoretical capacity based on the alloying reaction mechanism, and safe operating voltage. However, the large radius of K⁺ inevitably induces severe volume expansion in depotassiation/potassiation, and the sluggish kinetics of K⁺ insertion/extraction limits its further development. Herein, we summarize the strategies used to improve the potassium storage properties of various types of materials and introduce recent advances in the design and fabrication of favorable structural features of bismuth-based materials. Firstly, this review analyzes the structure, working mechanism and advantages and disadvantages of various types of materials for potassium storage. Then, based on this, the manuscript focuses on summarizing modification strategies including structural and morphological design, compositing with other materials, and electrolyte optimization, and elucidating the advantages of various modifications in enhancing the potassium storage performance. Finally, we outline the current challenges of bismuth-based materials in PIBs and put forward some prospects to be verified.

Highlights:
1 Various bismuth-based materials used in potassium-ion batteries (PIBs) anode are classified and overviewed, and the structure and potassium storage mechanism of various materials are discussed.
2 The advantages and challenges of different PIBs anode materials are pointed out, and the existing modification strategies to improve potassium storage are summarized.
3 The promising research directions of bismuth-based anode materials are proposed.

Advances in TENGs for Marine Energy Harvesting and In Situ Electrochemistry

2025-02-07T06:11:16+00:00

The large-scale use of ample marine energy will be one of the most important ways for human to achieve sustainable development through carbon neutral development plans. As a burgeoning technological method for electromechanical conversion, triboelectric nanogenerator (TENG) has significant advantages in marine energy for its low weight, cost-effectiveness, and high efficiency in low-frequency range. It can realize the efficient and economical harvesting of low-frequency blue energy by constructing the floating marine energy harvesting TENG. This paper firstly introduces the power transfer process and structural composition of TENG for marine energy harvesting in detail. In addition, the latest research works of TENG on marine energy harvesting in basic research and structural design are systematically reviewed by category. Finally, the advanced research progress in the power take-off types and engineering study of TENG with the marine energy are comprehensively generalized. Importantly, the challenges and problems faced by TENG in marine energy and in situ electrochemical application are summarized and the corresponding prospects and suggestions are proposed for the subsequent development direction and prospects to look forward to promoting the commercialization process of this field.

Highlights:
1 The basic information of triboelectric nanogenerator (TENG), the power conversion process, and key points of the marine energy harvesting TENGs was introduced in detail.
2 An in-depth introduction and analysis of relevant research with the marine energy harvesting were conducted through gradient classification.
3 This review not only provided a deeper summary of the latest research progress, discoveries, and challenges, but also made a rational outlook on solutions to related issues and future development directions.

Molecular Mechanism Behind the Capture of Fluorinated Gases by Metal–Organic Frameworks

2025-02-04T10:43:47+00:00

Fluorinated gases (F-gases) play a vital role in the chemical industry and in the fields of air conditioning, refrigeration, health care, and organic synthesis. However, the direct emission of waste gases containing F-gases into the atmosphere contributes to greenhouse effects and generates toxic substances. Developing porous materials for the energy-efficient capture, separation, and recovery of F-gases is highly desired. Recently, as a highly designable porous adsorbents, metal–organic frameworks (MOFs) exhibit excellent selective sorption performance toward F-gases, especially for the recognition and separation of different F-gases with highly similar properties, showing their great potential in F-gases control and recovery. In this review, we discuss the capture and separation of F-gases and their azeotropic, near-azeotropic, and isomeric mixtures in various application scenarios by MOFs, specifically classify and analyze molecular interaction between F-gases and MOFs, and interpret the mechanisms underlying their high performance regarding both adsorption capacity and selectivity, providing a repertoire for future materials design. Challenges faced in the transformation research roadmap of MOFs adsorbent separation technologies toward F-gases are also discussed, and areas for future research endeavors are highlighted.

Highlights:
1 The progress of metal–organic frameworks (MOFs) in capturing and separating F-gases is highlighted.
2 The molecular mechanisms of adsorption and separation are classified and analyzed.
3 Toolboxes of MOFs structural design for fluorinated gases separation are provided.

Membranes of Polymer of Intrinsic Microporosity PIM-1 for Gas Separation: Modification Strategies and Meta-Analysis

2025-02-04T03:25:17+00:00

Polymers of intrinsic microporosity (PIMs) have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades, owing to their highly permeable porous structures. However, challenges regarding its relatively low selectivity, physical aging, and plasticisation impede relevant industrial adoptions for gas separation. To address these issues, several strategies including chain modification, post-modification, blending with other polymers, and the addition of fillers, have been developed and explored. PIM-1 is the most investigated PIMs, and hence here we review the state-of-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementioned challenges via meta-analysis. Additionally, the development of PIM-1-based thin film composite membranes is commented as well, shedding light on their potential in industrial gas separation. We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.

Highlights:
1 Critical review of the polymers of intrinsic microporosity (PIM)-1-based membranes for applications in selective CO₂ separation.
2 State-of-the-art modification strategies for PIM-1 are thoroughly compared via meta-analysis.
3 Key perspectives for progressing PIM-1 thin film membranes towards practical applications are suggested.

Comprehensive Chlorine Suppression: Advances in Materials and System Technologies for Direct Seawater Electrolysis

2025-01-27T08:03:59+00:00

Seawater electrolysis offers a promising pathway to generate green hydrogen, which is crucial for the net-zero emission targets. Indirect seawater electrolysis is severely limited by high energy demands and system complexity, while the direct seawater electrolysis bypasses pre-treatment, offering a simpler and more cost-effective solution. However, the chlorine evolution reaction and impurities in the seawater lead to severe corrosion and hinder electrolysis’s efficiency. Herein, we review recent advances in the rational design of chlorine-suppressive catalysts and integrated electrolysis systems architectures for chloride-induced corrosion, with simultaneous enhancement of Faradaic efficiency and reduction of electrolysis’s cost. Furthermore, promising directions are proposed for durable and efficient seawater electrolysis systems. This review provides perspectives for seawater electrolysis toward sustainable energy conversion and environmental protection.

Highlights:
1 Rational design of chlorine-suppressing catalysts based on mechanistic insights.
2 Overview of recent advances in cutting-edge seawater electrolysis systems.
3 Discussion of challenges and potential directions for direct seawater electrolysis enhancement.

Wearable Biodevices Based on Two-Dimensional Materials: From Flexible Sensors to Smart Integrated Systems

2025-01-25T02:32:03+00:00

The proliferation of wearable biodevices has boosted the development of soft, innovative, and multifunctional materials for human health monitoring. The integration of wearable sensors with intelligent systems is an overwhelming tendency, providing powerful tools for remote health monitoring and personal health management. Among many candidates, two-dimensional (2D) materials stand out due to several exotic mechanical, electrical, optical, and chemical properties that can be efficiently integrated into atomic-thin films. While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene, the rapid development of new 2D materials with exotic properties has opened up novel applications, particularly in smart interaction and integrated functionalities. This review aims to consolidate recent progress, highlight the unique advantages of 2D materials, and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices. We begin with an in-depth analysis of the advantages, sensing mechanisms, and potential applications of 2D materials in wearable biodevice fabrication. Following this, we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body. Special attention is given to showcasing the integration of multi-functionality in 2D smart devices, mainly including self-power supply, integrated diagnosis/treatment, and human–machine interaction. Finally, the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of 2D materials for advanced biodevices.

Highlights:
1 Two-dimensional (2D) materials are highlighted for their exceptional mechanical, electrical, optical, and chemical properties, making them ideal for fabricating high-performance wearable biodevices.
2 The review categorizes cutting-edge wearable biodevices by their interactions with physical, electrophysiological, and biochemical signals, showcasing how 2D materials enhance these devices' functionality, mainly including self-powering and human-machine interaction.
3 2D materials enable multifunctional, high-performance biodevices, integrating self-powered systems, treatment platforms, and human-machine interactions, though challenges remain in practical applications.

Advancements in Passive Wireless Sensing Systems in Monitoring Harsh Environment and Healthcare Applications

2025-01-14T12:20:35+00:00

Recent advancements in passive wireless sensor technology have significantly extended the application scope of sensing, particularly in challenging environments for monitoring industry and healthcare applications. These systems are equipped with battery-free operation, wireless connectivity, and are designed to be both miniaturized and lightweight. Such features enable the safe, real-time monitoring of industrial environments and support high-precision physiological measurements in confined internal body spaces and on wearable epidermal devices. Despite the exploration into diverse application environments, the development of a systematic and comprehensive research framework for system architecture remains elusive, which hampers further optimization of these systems. This review, therefore, begins with an examination of application scenarios, progresses to evaluate current system architectures, and discusses the function of each component—specifically, the passive sensor module, the wireless communication model, and the readout module—within the context of key implementations in target sensing systems. Furthermore, we present case studies that demonstrate the feasibility of proposed classified components for sensing scenarios, derived from this systematic approach. By outlining a research trajectory for the application of passive wireless systems in sensing technologies, this paper aims to establish a foundation for more advanced, user-friendly applications.

Highlights:
1 This review comprehensively examines recent advancements in passive wireless systems applied to industrial environments and biomedical sensing, with a particular focus on the design strategies of passive wireless systems.
2 The design principles and operational mechanisms of passive wireless system components (sensing modules and readout modules) are systematically categorized.
3 Based on the latest research, the review highlights the innovative applications of passive wireless concepts in industrial environments, equipment safety, as well as in vivo and surface signal detection.

Photolithographic Microfabrication of Microbatteries for On-Chip Energy Storage

2025-01-11T11:06:59+00:00

Microbatteries (MBs) are crucial to power miniaturized devices for the Internet of Things. In the evolutionary journey of MBs, fabrication technology emerges as the cornerstone, guiding the intricacies of their configuration designs, ensuring precision, and facilitating scalability for mass production. Photolithography stands out as an ideal technology, leveraging its unparalleled resolution, exceptional design flexibility, and entrenched position within the mature semiconductor industry. However, comprehensive reviews on its application in MB development remain scarce. This review aims to bridge that gap by thoroughly assessing the recent status and promising prospects of photolithographic microfabrication for MBs. Firstly, we delve into the fundamental principles and step-by-step procedures of photolithography, offering a nuanced understanding of its operational mechanisms and the criteria for photoresist selection. Subsequently, we highlighted the specific roles of photolithography in the fabrication of MBs, including its utilization as a template for creating miniaturized micropatterns, a protective layer during the etching process, a mold for soft lithography, a constituent of MB active component, and a sacrificial layer in the construction of micro-Swiss-roll structure. Finally, the review concludes with a summary of the key challenges and future perspectives of MBs fabricated by photolithography, providing comprehensive insights and sparking research inspiration in this field.

Highlights:
1 The fundamental principles and step-by-step procedures of photolithography are introduced, and a nuanced understanding of its operational mechanisms and the criteria for photoresist selection is offered.
2 Various specific roles that photolithography plays in microbatteries (MBs) fabrication, including templates for 2D and 3D micropatterns, MB active components, and the sacrificial layer for constructing micro-Swiss-roll structure, are elaborated.
3 The challenges and future directions of MBs fabricated using photolithography, including materials selection, packaging techniques, application, and performance evaluation, are discussed.

Local Strain Engineering of Two-Dimensional Transition Metal Dichalcogenides Towards Quantum Emitters

2025-01-11T10:50:21+00:00

Two-dimensional transition metal dichalcogenides (2D TMDCs) have received considerable attention in local strain engineering due to their extraordinary mechanical flexibility, electonic structure, and optical properties. The strain-induced out-of-plane deformations in 2D TMDCs lead to diverse excitonic behaviors and versatile modulations in optical properties, paving the way for the development of advanced quantum technologies, flexible optoelectronic materials, and straintronic devices. Research on local strain engineering on 2D TMDCs has been delved into fabrication techniques, electronic state variations, and quantum optical applications. This review begins by summarizing the state-of-the-art methods for introducing local strain into 2D TMDCs, followed by an exploration of the impact of local strain engineering on optical properties. The intriguing phenomena resulting from local strain, such as exciton funnelling and anti-funnelling, are also discussed. We then shift the focus to the application of locally strained 2D TMDCs as quantum emitters, with various strategies outlined for modulating the properties of TMDC-based quantum emitters. Finally, we discuss the remaining questions in this field and provide an outlook on the future of local strain engineering on 2D TMDCs.

Highlights:
1 Methods for creating the local deformation in two-dimensional transition metal dichalcogenides (2D TMDCs) are introduced.
2 Modulations of local strain on their optical properties and excitonic behaviors are discussed.
3 Quantum emitters based on strained 2D TMDCs and other applications are presented.

Plant Cell Wall-Like Soft Materials: Micro- and Nanoengineering, Properties, and Applications

2025-01-11T05:08:36+00:00

Plant cell wall (CW)-like soft materials, referred to as artificial CWs, are composites of assembled polymers containing micro-/nanoparticles or fibers/fibrils that are designed to mimic the composition, structure, and mechanics of plant CWs. CW-like materials have recently emerged to test hypotheses pertaining to the intricate structure–property relationships of native plant CWs or to fabricate functional materials. Here, research on plant CWs and CW-like materials is reviewed by distilling key studies on biomimetic composites primarily composed of plant polysaccharides, including cellulose, pectin, and hemicellulose, as well as organic polymers like lignin. Micro- and nanofabrication of plant CW-like composites, characterization techniques, and in silico studies are reviewed, with a brief overview of current and potential applications. Micro-/nanofabrication approaches include bacterial growth and impregnation, layer-by-layer assembly, film casting, 3-dimensional templating microcapsules, and particle coating. Various characterization techniques are necessary for the comprehensive mechanical, chemical, morphological, and structural analyses of plant CWs and CW-like materials. CW-like materials demonstrate versatility in real-life applications, including biomass conversion, pulp and paper, food science, construction, catalysis, and reaction engineering. This review seeks to facilitate the rational design and thorough characterization of plant CW-mimetic materials, with the goal of advancing the development of innovative soft materials and elucidating the complex structure–property relationships inherent in native CWs.

Highlights:
1 This review provides a detailed account of engineered plant cell wall (CW)-mimetic soft materials, which are designed to replicate the intricate composition, structure, and mechanical properties of natural plant CWs.
2 Experimental methods to create CW-like materials are reviewed, and relevant characterization techniques, including mechanical, chemical, structural, and morphological analyses, are discussed.
3 The applications of CW-like materials in several fields, including food packaging, edible films, drug delivery, construction materials, and biocatalysis are highlighted.

Lessons from Nature: Advances and Perspectives in Bionic Microwave Absorption Materials

2025-01-02T03:02:41+00:00

Inspired by the remarkable electromagnetic response capabilities of the complex morphologies and subtle microstructures evolved by natural organisms, this paper delves into the research advancements and future application potential of bionic microwave-absorbing materials (BMAMs). It outlines the significance of achieving high-performance microwave-absorbing materials through ingenious microstructural design and judicious composition selection, while emphasizing the innovative strategies offered by bionic manufacturing. Furthermore, this work meticulously analyzes how inspiration can be drawn from the intricate structures of marine organisms, plants, animals, and non-metallic minerals in nature to devise and develop BMAMs with superior electromagnetic wave absorption properties. Additionally, the paper provides an in-depth exploration of the theoretical underpinnings of BMAMs, particularly the latest breakthroughs in broadband absorption. By incorporating advanced methodologies such as simulation modeling and bionic gradient design, we unravel the scientific principles governing the microwave absorption mechanisms of BMAMs, thereby furnishing a solid theoretical foundation for understanding and optimizing their performance. Ultimately, this review aims to offer valuable insights and inspiration to researchers in related fields, fostering the collective advancement of research on BMAMs.

Highlights:
1 This review describes the classification of bionic objects of bionic wave-absorbing materials in detail. From marine organisms, insects, plants to animals, different bionic objects will bring diversified influences and applications.
2 The multifunctional applications of bionic microwave absorption materials are systematically introduced in this paper, from microwave absorption to anti-corrosion, to mechanics, electronics, wearable devices, etc.
3 The theoretical basis and simulation calculation of bionic microwave absorption materials are also discussed.

Recent Advances in Wide-Range Temperature Metal-CO2 Batteries: A Mini Review

2025-01-02T02:52:15+00:00

The metal–carbon dioxide batteries, emerging as high-energy–density energy storage devices, enable direct CO₂ utilization, offering promising prospects for CO₂ capture and utilization, energy conversion, and storage. However, the electrochemical performance of M-CO₂ batteries faces significant challenges, particularly at extreme temperatures. Issues such as high overpotential, poor charge reversibility, and cycling capacity decay arise from complex reaction interfaces, sluggish oxidation kinetics, inefficient catalysts, dendrite growth, and unstable electrolytes. Despite significant advancements at room temperature, limited research has focused on the performance of M-CO₂ batteries across a wide-temperature range. This review examines the effects of low and high temperatures on M-CO₂ battery components and their reaction mechanism, as well as the advancements made in extending operational ranges from room temperature to extremely low and high temperatures. It discusses strategies to enhance electrochemical performance at extreme temperatures and outlines opportunities, challenges, and future directions for the development of M-CO₂ batteries.

Highlights:
1 This review provides a comprehensive overview of the current research progress on metal–carbon dioxide (M-CO₂) batteries across a broad temperature range (from room temperature to low/high temperatures).
2 The challenges encountered by M-CO₂ batteries under extreme low- and high-temperature conditions thoroughly discussed, along with strategies to address these challenges.
3 The potential application scenarios and future directions of M-CO₂ batteries across a broad temperature range are highlighted.

Next-Generation Desalination Membranes Empowered by Novel Materials: Where Are We Now?

2024-12-20T05:40:23+00:00

Membrane desalination is an economical and energy-efficient method to meet the current worldwide water scarcity. However, state-of-the-art reverse osmosis membranes are gradually being replaced by novel membrane materials as a result of ongoing technological advancements. These novel materials possess intrinsic pore structures or can be assembled to form lamellar membrane channels for selective transport of water or solutes (e.g., NaCl). Still, in real applications, the results fall below the theoretical predictions, and a few properties, including large-scale fabrication, mechanical strength, and chemical stability, also have an impact on the overall effectiveness of those materials. In view of this, we develop a new evaluation framework in the form of radar charts with five dimensions (i.e., water permeance, water/NaCl selectivity, membrane cost, scale of development, and stability) to assess the advantages, disadvantages, and potential of state-of-the-art and newly developed desalination membranes. In this framework, the reported thin film nanocomposite membranes and membranes developed from novel materials were compared with the state-of-the-art thin film composite membranes. This review will demonstrate the current advancements in novel membrane materials and bridge the gap between different desalination membranes. In this review, we also point out the prospects and challenges of next-generation membranes for desalination applications. We believe that this comprehensive framework may be used as a future reference for designing next-generation desalination membranes and will encourage further research and development in the field of membrane technology, leading to new insights and advancements.

Highlights:
1 The theoretical separation performance and practical separation performance of various membranes were collected and compared.
2 An up-to-date holistic and systematic evaluation of membranes from five dimensions (i.e., water permeance, water/NaCl selectivity, membrane cost, scale of development, and stability) is provided and visualized by radar charts.
3 The critical deficiencies revealed in the review are important in guiding the development of next-generation reverse osmosis membranes.

Precision-Engineered Construction of Proton-Conducting Metal–Organic Frameworks

2024-12-13T03:36:20+00:00

Proton-conducting materials have attracted considerable interest because of their extensive application in energy storage and conversion devices. Among them, metal–organic frameworks (MOFs) present tremendous development potential and possibilities for constructing novel advanced proton conductors due to their special advantages in crystallinity, designability, and porosity. In particular, several special design strategies for the structure of MOFs have opened new doors for the advancement of MOF proton conductors, such as charged network construction, ligand functionalization, metal-center manipulation, defective engineering, guest molecule incorporation, and pore-space manipulation. With the implementation of these strategies, proton-conducting MOFs have developed significantly and profoundly within the last decade. Therefore, in this review, we critically discuss and analyze the fundamental principles, design strategies, and implementation methods targeted at improving the proton conductivity of MOFs through representative examples. Besides, the structural features, the proton conduction mechanism and the behavior of MOFs are discussed thoroughly and meticulously. Future endeavors are also proposed to address the challenges of proton-conducting MOFs in practical research. We sincerely expect that this review will bring guidance and inspiration for the design of proton-conducting MOFs and further motivate the research enthusiasm for novel proton-conducting materials.

Highlights:
1 The effects of the size structure and stability of metal–organic frameworks (MOFs) on proton conduction are comprehensively summarized.
2 Advanced strategies for constructing proton conduction MOFs are critically discussed.
3 Challenges and opportunities for the development of novel proton-conducting MOFs are further outlined.

Tailoring Cathode–Electrolyte Interface for High-Power and Stable Lithium–Sulfur Batteries

2024-12-06T08:19:32+00:00

Global interest in lithium–sulfur batteries as one of the most promising energy storage technologies has been sparked by their low sulfur cathode cost, high gravimetric, volumetric energy densities, abundant resources, and environmental friendliness. However, their practical application is significantly impeded by several serious issues that arise at the cathode–electrolyte interface, such as interface structure degradation including the uneven deposition of Li₂S, unstable cathode–electrolyte interphase (CEI) layer and intermediate polysulfide shuttle effect. Thus, an optimized cathode–electrolyte interface along with optimized electrodes is required for overall improvement. Herein, we comprehensively outline the challenges and corresponding strategies, including electrolyte optimization to create a dense CEI layer, regulating the Li₂S deposition pattern, and inhibiting the shuttle effect with regard to the solid–liquid–solid pathway, the transformation from solid–liquid–solid to solid–solid pathway, and solid–solid pathway at the cathode–electrolyte interface. In order to spur more perceptive research and hasten the widespread use of lithium–sulfur batteries, viewpoints on designing a stable interface with a deep comprehension are also put forth.

Highlights:
1 This review delves into the mechanism of the state-of-the-art lithium–sulfur batteries from a novel perspective of cathode–electrolyte interface.
2 It provides extensive strategies to construct a stable cathode–electrolyte interphase layer and improve the uneven deposition of Li₂S, enhancing the stability of the interface structure.
3 It proposes an in-depth and comprehensive research on how to inhibit the shuttle effect at the cathode–electrolyte interface with regard to distinct reaction pathways.

Atomically Precise Cu Nanoclusters: Recent Advances, Challenges, and Perspectives in Synthesis and Catalytic Applications

2024-12-06T07:43:33+00:00

Atomically precise metal nanoclusters are an emerging type of nanomaterial which has diverse interfacial metal–ligand coordination motifs that can significantly affect their physicochemical properties and functionalities. Among that, Cu nanoclusters have been gaining continuous increasing research attentions, thanks to the low cost, diversified structures, and superior catalytic performance for various reactions. In this review, we first summarize the recent progress regarding the synthetic methods of atomically precise Cu nanoclusters and the coordination modes between Cu and several typical ligands and then discuss the catalytic applications of these Cu nanoclusters with some explicit examples to explain the atomical-level structure–performance relationship. Finally, the current challenges and future research perspectives with some critical thoughts are elaborated. We hope this review can not only provide a whole picture of the current advances regarding the synthesis and catalytic applications of atomically precise Cu nanoclusters, but also points out some future research visions in this rapidly booming field.

Highlights:
1 Summarizing recent advances on synthesis and catalytic applications of Cu nanoclusters.
2 The structure–property–functionality relationship is clearly elucidated.
3 Critical analysis of the current challenges and future perspectives.

Advances in the Development of Gradient Scaffolds Made of Nano-Micromaterials for Musculoskeletal Tissue Regeneration

2024-12-01T08:55:36+00:00

The intricate hierarchical structure of musculoskeletal tissues, including bone and interface tissues, necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes. This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes. Building on the anatomical characteristics of bone and interfacial tissues, this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues, specifically focusing on methods used to construct compositional and structural gradients within the scaffolds. The latest applications of gradient scaffolds for the regeneration of bone, osteochondral, and tendon-to-bone interfaces are presented. Furthermore, the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed, as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.

Highlights:
1 This review highlights the gradient variations in the structural composition of musculoskeletal tissues and comprehensively examines recent progress in the fabrication and application of biomimetic gradient scaffolds for musculoskeletal repair.
2 The challenges and prospects of gradient scaffolds for clinical application are discussed.

Recent Strategies and Advances in Hydrogel-Based Delivery Platforms for Bone Regeneration

2024-12-01T08:18:24+00:00

Bioactive molecules have shown great promise for effectively regulating various bone formation processes, rendering them attractive therapeutics for bone regeneration. However, the widespread application of bioactive molecules is limited by their low accumulation and short half-lives in vivo. Hydrogels have emerged as ideal carriers to address these challenges, offering the potential to prolong retention times at lesion sites, extend half-lives in vivo and mitigate side effects, avoid burst release, and promote adsorption under physiological conditions. This review systematically summarizes the recent advances in the development of bioactive molecule-loaded hydrogels for bone regeneration, encompassing applications in cranial defect repair, femoral defect repair, periodontal bone regeneration, and bone regeneration with underlying diseases. Additionally, this review discusses the current strategies aimed at improving the release profiles of bioactive molecules through stimuli-responsive delivery, carrier-assisted delivery, and sequential delivery. Finally, this review elucidates the existing challenges and future directions of hydrogel encapsulated bioactive molecules in the field of bone regeneration.

Highlights:
1 Recent advances in the combined delivery platform that integrate nano-/microscale carriers and with 3D hydrogel network for bone regeneration are summarized.
2 The strategies for bioactive molecules delivery involving nanoparticles, nanosheets, and microspheres, along with extra stimuli such as near-infrared light, temperature changes, ultrasonication, and inflammatory conditions, are introduced.
3 The prospects and challenges for the clinical translation and the development of nano-/microscale incorporated hydrogel-based delivery platform are discussed.

Recent Advances in Artificial Sensory Neurons: Biological Fundamentals, Devices, Applications, and Challenges

2024-11-16T08:31:39+00:00

Spike-based neural networks, which use spikes or action potentials to represent information, have gained a lot of attention because of their high energy efficiency and low power consumption. To fully leverage its advantages, converting the external analog signals to spikes is an essential prerequisite. Conventional approaches including analog-to-digital converters or ring oscillators, and sensors suffer from high power and area costs. Recent efforts are devoted to constructing artificial sensory neurons based on emerging devices inspired by the biological sensory system. They can simultaneously perform sensing and spike conversion, overcoming the deficiencies of traditional sensory systems. This review summarizes and benchmarks the recent progress of artificial sensory neurons. It starts with the presentation of various mechanisms of biological signal transduction, followed by the systematic introduction of the emerging devices employed for artificial sensory neurons. Furthermore, the implementations with different perceptual capabilities are briefly outlined and the key metrics and potential applications are also provided. Finally, we highlight the challenges and perspectives for the future development of artificial sensory neurons.

Highlights:
1 Biological fundamentals and recent progress of artificial sensory neurons are systematically reviewed.
2 Basic device, performance metrics, and potential applications of artificial sensory neurons are summarized.
3 Challenges for the future development of artificial sensory neurons are discussed.

Smart Gas Sensors: Recent Developments and Future Prospective

2024-11-05T02:40:15+00:00

Gas sensor is an indispensable part of modern society with wide applications in environmental monitoring, healthcare, food industry, public safety, etc. With the development of sensor technology, wireless communication, smart monitoring terminal, cloud storage/computing technology, and artificial intelligence, smart gas sensors represent the future of gas sensing due to their merits of real-time multifunctional monitoring, early warning function, and intelligent and automated feature. Various electronic and optoelectronic gas sensors have been developed for high-performance smart gas analysis. With the development of smart terminals and the maturity of integrated technology, flexible and wearable gas sensors play an increasing role in gas analysis. This review highlights recent advances of smart gas sensors in diverse applications. The structural components and fundamental principles of electronic and optoelectronic gas sensors are described, and flexible and wearable gas sensor devices are highlighted. Moreover, sensor array with artificial intelligence algorithms and smart gas sensors in “Internet of Things” paradigm are introduced. Finally, the challenges and perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.

Highlights:
1 Recent developments of advanced electronic and optoelectronic gas sensors are introduced.
2 Sensor array with artificial intelligence algorithms and smart gas sensors in “Internet of Things” paradigm are highlighted.
3 Applications of smart gas sensors in environmental monitoring, medical and healthcare applications, food quality control, and public safety are described.

Solution-Processed Thin Film Transparent Photovoltaics: Present Challenges and Future Development

2024-10-26T09:41:34+00:00

Electrical energy is essential for modern society to sustain economic growths. The soaring demand for the electrical energy, together with an awareness of the environmental impact of fossil fuels, has been driving a shift towards the utilization of solar energy. However, traditional solar energy solutions often require extensive spaces for a panel installation, limiting their practicality in a dense urban environment. To overcome the spatial constraint, researchers have developed transparent photovoltaics (TPV), enabling windows and facades in vehicles and buildings to generate electric energy. Current TPV advancements are focused on improving both transparency and power output to rival commercially available silicon solar panels. In this review, we first briefly introduce wavelength- and non-wavelength-selective strategies to achieve transparency. Figures of merit and theoretical limits of TPVs are discussed to comprehensively understand the status of current TPV technology. Then we highlight recent progress in different types of TPVs, with a particular focus on solution-processed thin-film photovoltaics (PVs), including colloidal quantum dot PVs, metal halide perovskite PVs and organic PVs. The applications of TPVs are also reviewed, with emphasis on agrivoltaics, smart windows and facades. Finally, current challenges and future opportunities in TPV research are pointed out.

Highlights:
1 Recent advancement in solution-processed thin film transparent photovoltaics (TPVs) is summarized, including perovskites, organics, and colloidal quantum dots.
2 Pros and cons of the emerging TPVs are analyzed according to the materials characteristics and the application requirements on the aesthetics and energy generation.
3 Promising TPV applications are discussed with emphasis on agrivoltaics, smart windows and facades.

Unleashing the Potential of Electroactive Hybrid Biomaterials and Self-Powered Systems for Bone Therapeutics

2024-10-21T02:16:49+00:00

The incidence of large bone defects caused by traumatic injury is increasing worldwide, and the tissue regeneration process requires a long recovery time due to limited self-healing capability. Endogenous bioelectrical phenomena have been well recognized as critical biophysical factors in bone remodeling and regeneration. Inspired by bioelectricity, electrical stimulation has been widely considered an external intervention to induce the osteogenic lineage of cells and enhance the synthesis of the extracellular matrix, thereby accelerating bone regeneration. With ongoing advances in biomaterials and energy-harvesting techniques, electroactive biomaterials and self-powered systems have been considered biomimetic approaches to ensure functional recovery by recapitulating the natural electrophysiological microenvironment of healthy bone tissue. In this review, we first introduce the role of bioelectricity and the endogenous electric field in bone tissue and summarize different techniques to electrically stimulate cells and tissue. Next, we highlight the latest progress in exploring electroactive hybrid biomaterials as well as self-powered systems such as triboelectric and piezoelectric-based nanogenerators and photovoltaic cell-based devices and their implementation in bone tissue engineering. Finally, we emphasize the significance of simulating the target tissue’s electrophysiological microenvironment and propose the opportunities and challenges faced by electroactive hybrid biomaterials and self-powered bioelectronics for bone repair strategies.

Highlights:
1 Introduce the role of bioelectricity and the endogenous electric field in bone tissue and summarize different techniques to electrically stimulate cells and tissue.
2 Highlight the latest progress in exploring electroactive hybrid biomaterials as well as self-powered systems such as triboelectric and piezoelectric-based nanogenerators and photovoltaic cell-based devices in bone tissue engineering.
3 Emphasize the significance of simulating the target tissue’s electrophysiological microenvironment and propose the opportunities and challenges faced by electroactive hybrid biomaterials and self-powered bioelectronics.

Molecular Structure Tailoring of Organic Spacers for High-Performance Ruddlesden–Popper Perovskite Solar Cells

2024-10-15T02:04:43+00:00

Layer-structured Ruddlesden–Popper (RP) perovskites (RPPs) with decent stability have captured the imagination of the photovoltaic research community and bring hope for boosting the development of perovskite solar cell (PSC) technology. However, two-dimensional (2D) or quasi-2D RP PSCs are encountered with some challenges of the large exciton binding energy, blocked charge transport and poor film quality, which restrict their photovoltaic performance. Fortunately, these issues can be readily resolved by rationally designing spacer cations of RPPs. This review mainly focuses on how to design the molecular structures of organic spacers and aims to endow RPPs with outstanding photovoltaic applications. We firstly elucidated the important roles of organic spacers in impacting crystallization kinetics, charge transporting ability and stability of RPPs. Then we brought three aspects to attention for designing organic spacers. Finally, we presented the specific molecular structure design strategies for organic spacers of RPPs aiming to improve photovoltaic performance of RP PSCs. These proposed strategies in this review will provide new avenues to develop novel organic spacers for RPPs and advance the development of RPP photovoltaic technology for future applications.

Highlights:
1 Organic spacers in Ruddlesden–Popper (RP) perovskites play a vital role in tuning crystallization, charge transport and photovoltaic performance for RP perovskite solar cells (PSCs).
2 Fundamental understanding of the functions of molecular structure of organic spacers is the prerequisite to design high-performance PSCs.
3 This review proposes practical design strategies in seeking RP molecular structure to maximize its photovoltaic performance for PSCs.

Flexible Graphene Field-Effect Transistors and Their Application in Flexible Biomedical Sensing

2024-10-09T01:38:23+00:00

Flexible electronics are transforming our lives by making daily activities more convenient. Central to this innovation are field-effect transistors (FETs), valued for their efficient signal processing, nanoscale fabrication, low-power consumption, fast response times, and versatility. Graphene, known for its exceptional mechanical properties, high electron mobility, and biocompatibility, is an ideal material for FET channels and sensors. The combination of graphene and FETs has given rise to flexible graphene field-effect transistors (FGFETs), driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors. Here, we first provide a brief overview of the basic structure, operating mechanism, and evaluation parameters of FGFETs, and delve into their material selection and patterning techniques. The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities. We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors, focusing on the key aspects of constructing high-quality flexible biomedical sensors. Finally, we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors. This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.

Highlights:
1 The review provides a brief overview of the basic structure, operating mechanism, and key performance indicators of flexible graphene field-effect transistors.
2 The review details the preparation strategy of flexible graphene field-effect transistors focusing on material selection and patterning techniques.
3 The review analyzes the latest strategies for developing wearable and implantable flexible biomedical sensors based on flexible graphene field-effect transistors.

Optimization Strategies of Na3V2(PO4)3 Cathode Materials for Sodium-Ion Batteries

2024-10-09T01:28:54+00:00

Na₃V₂(PO₄)₃ (NVP) has garnered great attentions as a prospective cathode material for sodium-ion batteries (SIBs) by virtue of its decent theoretical capacity, superior ion conductivity and high structural stability. However, the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density, which strictly confine its further application in SIBs. Thus, it is of significance to boost the sodium storage performance of NVP cathode material. Up to now, many methods have been developed to optimize the electrochemical performance of NVP cathode material. In this review, the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed, including carbon coating or modification, foreign-ion doping or substitution and nanostructure and morphology design. The foreign-ion doping or substitution is highlighted, involving Na, V, and PO₄³⁻ sites, which include single-site doping, multiple-site doping, single-ion doping, multiple-ion doping and so on. Furthermore, the challenges and prospects of high-performance NVP cathode material are also put forward. It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.

Highlights:
1 Optimization strategies for high-performance Na₃V₂(PO₄)₃ (NVP) cathode material are well summarized and discussed, including carbon coating or modification, foreign-ion doping or substitution and nanostructure and morphology design.
2 The foreign-ion doping or substitution is highlighted, involving the Na, V, and PO₄³⁻ sites, which include single-site doping, multiple-site doping, single-ion doping and multiple-ion doping.
3 Challenges and future perspectives for high-performance NVP cathode material are presented.

Engineered Cancer Nanovaccines: A New Frontier in Cancer Therapy

2024-10-03T06:29:48+00:00

Vaccinations are essential for preventing and treating disease, especially cancer nanovaccines, which have gained considerable interest recently for their strong anti-tumor immune capabilities. Vaccines can prompt the immune system to generate antibodies and activate various immune cells, leading to a response against tumor tissues and reducing the negative effects and recurrence risks of traditional chemotherapy and surgery. To enhance the flexibility and targeting of vaccines, nanovaccines utilize nanotechnology to encapsulate or carry antigens at the nanoscale level, enabling more controlled and precise drug delivery to enhance immune responses. Cancer nanovaccines function by encapsulating tumor-specific antigens or tumor-associated antigens within nanomaterials. The small size of these nanomaterials allows for precise targeting of T cells, dendritic cells, or cancer cells, thereby eliciting a more potent anti-tumor response. In this paper, we focus on the classification of carriers for cancer nanovaccines, the roles of different target cells, and clinically tested cancer nanovaccines, discussing strategies for effectively inducing cytotoxic T lymphocytes responses and optimizing antigen presentation, while also looking ahead to the translational challenges of moving from animal experiments to clinical trials.

Highlights:
1 We classified the carriers that built cancer nanovaccines, discussed their diversified applications and coincidently compared their advantages and disadvantages.
2 Various cellular targets that guide the design and engineering of cancer nanovaccines are categorized and their characteristics and benefits are highlighted.
3 The clinical cases and encountered challenges in cancer nanovaccines are discussed, during which reasonable solutions and future research direction are provided.

Recent Advances in Fibrous Materials for Hydroelectricity Generation

2024-10-03T06:17:47+00:00

Depleting fossil energy sources and conventional polluting power generation pose a threat to sustainable development. Hydroelectricity generation from ubiquitous and spontaneous phase transitions between liquid and gaseous water has been considered a promising strategy for mitigating the energy crisis. Fibrous materials with unique flexibility, processability, multifunctionality, and practicability have been widely applied for fibrous materials-based hydroelectricity generation (FHG). In this review, the power generation mechanisms, design principles, and electricity enhancement factors of FHG are first introduced. Then, the fabrication strategies and characteristics of varied constructions including 1D fiber, 1D yarn, 2D fabric, 2D membrane, 3D fibrous framework, and 3D fibrous gel are demonstrated. Afterward, the advanced functions of FHG during water harvesting, proton dissociation, ion separation, and charge accumulation processes are analyzed in detail. Moreover, the potential applications including power supply, energy storage, electrical sensor, and information expression are also discussed. Finally, some existing challenges are considered and prospects for future development are sincerely proposed.

Highlights:
1 Fundamental principles and characteristics of fibrous materials-based hydroelectricity generation (FHG) are thoroughly reviewed.
2 Fabrication strategies and advanced functions of FHG are discussed and summarized in detail.
3 Challenges and perspectives of the next-generation development of FHG are discussed.

Exploring Nanoscale Perovskite Materials for Next-Generation Photodetectors: A Comprehensive Review and Future Directions

2024-10-03T06:01:41+00:00

The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications. These materials are promising candidates for next-generation photodetectors (PDs) due to their unique optoelectronic properties and flexible synthesis routes. This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures, including quantum dots, nanosheets, nanorods, nanowires, and nanocrystals. Through a thorough analysis of recent literature, the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation. In addition, it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems. This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability, making it a valuable resource for researchers.

Highlights:
1 Innovative synthesis method for nanoscale-based perovskites with enhanced stability and efficiency.
2 Novel application of nanoscale-based perovskites in optoelectronics with superior performance metrics.
3 Comprehensive analysis of the structure–property relationships in perovskite nanomaterials.

High-Entropy Electrode Materials: Synthesis, Properties and Outlook

2024-10-02T05:53:24+00:00

High-entropy materials represent a new category of high-performance materials, first proposed in 2004 and extensively investigated by researchers over the past two decades. The definition of high-entropy materials has continuously evolved. In the last ten years, the discovery of an increasing number of high-entropy materials has led to significant advancements in their utilization in energy storage, electrocatalysis, and related domains, accompanied by a rise in techniques for fabricating high-entropy electrode materials. Recently, the research emphasis has shifted from solely improving the performance of high-entropy materials toward exploring their reaction mechanisms and adopting cleaner preparation approaches. However, the current definition of high-entropy materials remains relatively vague, and the preparation method of high-entropy materials is based on the preparation method of single metal/low- or medium-entropy materials. It should be noted that not all methods applicable to single metal/low- or medium-entropy materials can be directly applied to high-entropy materials. In this review, the definition and development of high-entropy materials are briefly reviewed. Subsequently, the classification of high-entropy electrode materials is presented, followed by a discussion of their applications in energy storage and catalysis from the perspective of synthesis methods. Finally, an evaluation of the advantages and disadvantages of various synthesis methods in the production process of different high-entropy materials is provided, along with a proposal for potential future development directions for high-entropy materials.

Highlights:
1 The developmental history of high-entropy materials and the conceptual origin of “high entropy” is comprehensively reviewed.
2 The preparation methods of various high-entropy electrode materials are comprehensively reviewed.
3 The application properties of various high-entropy electrode materials in electrocatalysis and energy storage are comprehensively reviewed, with a prospective outlook on the future development of such materials.

Advances in Graphene-Based Electrode for Triboelectric Nanogenerator

2024-10-01T06:12:56+00:00

With the continuous development of wearable electronics, wireless sensor networks and other micro-electronic devices, there is an increasingly urgent need for miniature, flexible and efficient nanopower generation technology. Triboelectric nanogenerator (TENG) technology can convert small mechanical energy into electricity, which is expected to address this problem. As the core component of TENG, the choice of electrode materials significantly affects its performance. Traditional metal electrode materials often suffer from problems such as durability, which limits the further application of TENG. Graphene, as a novel electrode material, shows excellent prospects for application in TENG owing to its unique structure and excellent electrical properties. This review systematically summarizes the recent research progress and application prospects of TENGs based on graphene electrodes. Various precision processing methods of graphene electrodes are introduced, and the applications of graphene electrode-based TENGs in various scenarios as well as the enhancement of graphene electrodes for TENG performance are discussed. In addition, the future development of graphene electrode-based TENGs is also prospectively discussed, aiming to promote the continuous advancement of graphene electrode-based TENGs.

Highlights:
1 Comprehensively reviewed the progress in research on graphene electrode-based triboelectric nanogenerators (TENGs) from two dimensions, including precision processing methods of graphene electrodes and applications of TENGs.
2 Discussed the various applications of graphene electrode-based TENGs in different scenarios, as well as the ways in which graphene electrodes enhance the performance of TENGs.
3 Offered a prospective discussion on the future development of graphene electrode-based TENGs, with the aim of promoting continuous advancements in this field.

Prussian Blue Analogue-Templated Nanocomposites for Alkali-Ion Batteries: Progress and Perspective

2024-09-30T07:32:49+00:00

Lithium-ion batteries (LIBs) have dominated the portable electronic and electrochemical energy markets since their commercialisation, whose high cost and lithium scarcity have prompted the development of other alkali-ion batteries (AIBs) including sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). Owing to larger ion sizes of Na⁺ and K⁺ compared with Li⁺, nanocomposites with excellent crystallinity orientation and well-developed porosity show unprecedented potential for advanced lithium/sodium/potassium storage. With enticing open rigid framework structures, Prussian blue analogues (PBAs) remain promising self-sacrificial templates for the preparation of various nanocomposites, whose appeal originates from the well-retained porous structures and exceptional electrochemical activities after thermal decomposition. This review focuses on the recent progress of PBA-derived nanocomposites from their fabrication, lithium/sodium/potassium storage mechanism, and applications in AIBs (LIBs, SIBs, and PIBs). To distinguish various PBA derivatives, the working mechanism and applications of PBA-templated metal oxides, metal chalcogenides, metal phosphides, and other nanocomposites are systematically evaluated, facilitating the establishment of a structure–activity correlation for these materials. Based on the fruitful achievements of PBA-derived nanocomposites, perspectives for their future development are envisioned, aiming to narrow down the gap between laboratory study and industrial reality.

Highlights:
1 The synthetic protocols of various Prussian blue analogue (PBA)-templated nanocomposites are discussed.
2 Alkali-ion storage mechanisms based on intercalation, alloying, or conversion reactions are analysed.
3 The properties of PBA-templated nanocomposites in alkali-ion batteries (AIBs) are evaluated and compared to outline the structure–activity correlation.
4 Perspectives for the future development of PBA-templated AIB electrodes are envisaged.

Defect Engineering: Can it Mitigate Strong Coulomb Effect of Mg2+ in Cathode Materials for Rechargeable Magnesium Batteries?

2024-09-25T05:20:40+00:00

Rechargeable magnesium batteries (RMBs) have been considered a promising “post lithium-ion battery” system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market. However, the sluggish diffusion kinetics of bivalent Mg²⁺ in the host material, related to the strong Coulomb effect between Mg²⁺ and host anion lattices, hinders their further development toward practical applications. Defect engineering, regarded as an effective strategy to break through the slow migration puzzle, has been validated in various cathode materials for RMBs. In this review, we first thoroughly understand the intrinsic mechanism of Mg²⁺ diffusion in cathode materials, from which the key factors affecting ion diffusion are further presented. Then, the positive effects of purposely introduced defects, including vacancy and doping, and the corresponding strategies for introducing various defects are discussed. The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized. Finally, the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.

Highlights:
1 The underlying migration mechanism of Mg²⁺ in cathode materials and roles of defects in Mg²⁺ migration in cathode materials were studied.
2 Applications of defect engineering to Mg²⁺ migration in cathode materials and the strategies for introducing various defects were summarized.
3 New development directions of defect engineering in cathode materials for rechargeable magnesium battery were prospected.

Advanced Functional Electromagnetic Shielding Materials: A Review Based on Micro-Nano Structure Interface Control of Biomass Cell Walls

2024-09-24T12:19:00+00:00

Research efforts on electromagnetic interference (EMI) shielding materials have begun to converge on green and sustainable biomass materials. These materials offer numerous advantages such as being lightweight, porous, and hierarchical. Due to their porous nature, interfacial compatibility, and electrical conductivity, biomass materials hold significant potential as EMI shielding materials. Despite concerted efforts on the EMI shielding of biomass materials have been reported, this research area is still relatively new compared to traditional EMI shielding materials. In particular, a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment, preparation process, and micro-control would be valuable. The preparation methods and characteristics of wood, bamboo, cellulose and lignin in EMI shielding field are critically discussed in this paper, and similar biomass EMI materials are summarized and analyzed. The composite methods and fillers of various biomass materials were reviewed. this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.

Highlights:
1 The advantages of biomass materials for electromagnetic interference (EMI) shielding are analyzed, the mechanism of EMI shielding is summarized, and the factors affecting EMI shielding are analyzed systematically.
2 Various biomass materials (wood, bamboo, lignin, cellulose) were modified to obtain unique structures and improve EMI shielding performance.
3 The problems encountered in the application of biomass materials for EMI shielding are summarized, and the potential development and application in the future are prospected.

Advancements and Challenges in Organic–Inorganic Composite Solid Electrolytes for All-Solid-State Lithium Batteries

2024-09-24T12:05:58+00:00

To address the limitations of contemporary lithium-ion batteries, particularly their low energy density and safety concerns, all-solid-state lithium batteries equipped with solid-state electrolytes have been identified as an up-and-coming alternative. Among the various SEs, organic–inorganic composite solid electrolytes (OICSEs) that combine the advantages of both polymer and inorganic materials demonstrate promising potential for large-scale applications. However, OICSEs still face many challenges in practical applications, such as low ionic conductivity and poor interfacial stability, which severely limit their applications. This review provides a comprehensive overview of recent research advancements in OICSEs. Specifically, the influence of inorganic fillers on the main functional parameters of OICSEs, including ionic conductivity, Li⁺ transfer number, mechanical strength, electrochemical stability, electronic conductivity, and thermal stability are systematically discussed. The lithium-ion conduction mechanism of OICSE is thoroughly analyzed and concluded from the microscopic perspective. Besides, the classic inorganic filler types, including both inert and active fillers, are categorized with special emphasis on the relationship between inorganic filler structure design and the electrochemical performance of OICSEs. Finally, the advanced characterization techniques relevant to OICSEs are summarized, and the challenges and perspectives on the future development of OICSEs are also highlighted for constructing superior ASSLBs.

Highlights:
1 The lithium-ion conduction mechanism of organic-inorganic composite solid electrolytes (OICSEs) is thoroughly conducted and concluded from the microscopic perspective based on filler content, type, and system.
2 The classic inorganic filler types, including inert and active fillers, are categorized with special emphasis on the relationship between inorganic filler structure design and the electrochemical performance of OICSEs.
3 Advanced characterization techniques for OICSEs are discussed, and the challenges and prospects for developing superior all-solid-state lithium batteries are highlighted.

Bimetallic Single-Atom Catalysts for Water Splitting

2024-09-25T07:48:11+00:00

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society. The field of catalysis has been revolutionized by single-atom catalysts (SACs), which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports. Recently, bimetallic SACs (bimSACs) have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports. BimSACs offer an avenue for rich metal–metal and metal–support cooperativity, potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges, substrate activation with reversible redox cycles, simultaneous multi-electron transfer, regulation of spin states, tuning of electronic properties, and cyclic transition states with low activation energies. This review aims to encapsulate the growing advancements in bimSACs, with an emphasis on their pivotal role in hydrogen generation via water splitting. We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs, elucidate their electronic properties, and discuss their local coordination environment. Overall, we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction, the two half-reactions of the water electrolysis process.

Highlights:
1 Bimetallic single-atom catalysts (bimSACs) have garnered significant attention for leveraging the synergistic functions of the two metal active centers.
2 This review focuses on the advancements in the field of bimSACs and their pivotal role in hydrogen generation via water splitting.
3 State-of-the-art computational and physicochemical techniques for the analysis of bimSACs and their application in electrocatalytic water splitting are discussed.