Issue

Vol. 18 (2026)

Synergistic Design of Flexible Nanopapers for High-Performance Proton Pseudocapacitors

https://doi.org/10.1007/s40820-025-01989-6
Jiayue Dong
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Zhaoqing Lu
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Li Hua
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Zizhan Guo
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Xiaoxu Xu
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Jinlong Wu
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Fengfeng Jia
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
Yuanming Wang
College of Bioresources Chemical and Materials Engineering, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China

Corresponding Author: Yuanming Wang

yminghit@sust.edu.cn

Nano-Micro Letters, Vol. 18 (2026), Article Number: 158

Abstract

Two-dimensional materials for flexible energy storage commonly face huge challenges in limited active surface and hindered charge transport. Herein, we report an innovative asymmetric pseudocapacitor based on synergistic design of modified MXene and graphene, integrating gas-induced rapid expansion technology and precise surface chemical regulation methods. For graphene modification, rapid vaporization induces exfoliation and expansion of graphene oxide layers. Subsequently, pseudocapacitive oxygen-containing groups were selectively introduced through acid oxidation, yielding expanded-and-oxidized graphene (OEG) for positive porous-nanopaper electrode. For MXene modification, alkali-treated MXene underwent hydrazine assistance to facilitate gas expansion and –NH2 grafting, producing MXene-NH2 (NOM) for negative porous-nanopaper electrode. Density functional theory calculations show that –COOH more effectively modulate graphene’s electronic structure by inducing charge redistribution and creating active sites, thereby enhancing H+ adsorption and ion interactions compared to –OH. Meanwhile, –NH2 on MXene enable electron delocalization and dynamic Ti–N–H+ interactions, speeding up proton adsorption/desorption and boosting both pseudocapacitance and conductivity. Through collaborative optimized spatial architecture and surface properties, flexible OEGB and NOMB exhibited of 333.6 and 500.5 F g−1 at high mass loading, respectively. The assembled proton pseudocapacitor readily achieved energy and power densities of 58.9 Wh kg−1 and 3802 W kg−1, respectively, with excellent stability for potential applications.


Highlights:
1 By utilizing water vaporization to increase the surface area of graphene and precisely controlling the ratio of oxygen-containing functional groups, the optimal –COOH:–OH ratio of 1:1 was successfully achieved, resulting in a maximum pseudocapacitance of 430.5 F g−1.
2 Through hydrazine-assisted hydrothermal reaction, –F groups on the MXene surface were substituted with –NH2, while gas generation facilitated the creation of a porous structure, boosting the capacitance to 500.5 F g−1 under high mass loading conditions.

Keywords

MXene Graphene Spatial architecture Surface chemistry Proton-type pseudocapacitor
Dong, Jiayue, Zhaoqing Lu, Li Hua, Zizhan Guo, Xiaoxu Xu, Jinlong Wu, Fengfeng Jia, and Yuanming Wang. 2026. “Synergistic Design of Flexible Nanopapers for High-Performance Proton Pseudocapacitors”. Nano-Micro Letters 18 (January):158. https://doi.org/10.1007/s40820-025-01989-6.
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