Fan, H.- li, Ran, F., Zhang, X.- xuan, Song, H.- ming, Niu, X.- qin, Kong, L.- bin, & Kang, L. (2014). Hollow Carbon Microspheres/MnO2 Nanosheets Composites: Hydrothermal Synthesis and Electrochemical Behaviors. Nano-Micro Letters, 7(1), 59-67. https://doi.org/10.1007/s40820-014-0019-z