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Chemical Research in Chinese Universities ›› 2020, Vol. 36 ›› Issue (1): 97-104.doi: 10.1007/s40242-020-9052-6

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Boosting the Energy Density of Flexible Asymmetric Supercapacitor with Three Dimensional Fe2O3 Composite Brush Anode

GAO Yuan1, ZHOU Ruitao1,2, WANG Dongrui1, HUANG Qiyao1, CHENG Ching-Hsiang2, ZHENG Zijian1   

  1. 1. Laboratory for Advanced Interfacial Materials and Devices, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong SAR, P. R. China;
    2. Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, P. R. China
  • Received:2019-11-19 Revised:2020-01-07 Online:2020-02-01 Published:2020-01-09
  • Contact: GAO Yuan, ZHENG Zijian E-mail:yuan.pu.gao@polyu.edu.hk;tczzheng@polyu.edu.hk
  • Supported by:
    Supported by the Project of The Hong Kong Polytechnic University, China(Nos.1-YW0Z and 1-ZVK1).

Abstract: Flexible asymmetric supercapacitor is fabricated with three dimensional(3D) Fe2O3/Ni(OH)2 composite brush anode and Ni(OH)2/MoO2 honeycomb cathode. Particularly for 3D composite brush anode, a layer of thin Fe2O3 film is firmly adhered on a 3D Ni brush current collector with the assist of Ni(OH)2, functioning as both adherence layer and pseudocapacitive active material. The unique 3D Ni brush current collector possesses large surface area and stretching architecture, which facilitate to achieve the composite anode with high gravimetric capacitance of 2158 F/g. In terms of cathode, Ni(OH)2 and MoO2 have a synergistic effect to improve the specific capacitance, and the resulting Ni(OH)2/MoO2 honeycomb cathode shows a very high gravimetric capacitance up to 3264 F/g. The asymmetric supercapacitor(ASC) has balanced cathode and anode, and exhibits an ultrahigh gravimetric capacitance of 1427 F/g and an energy density of 476 W·h/kg. The energy density of ASC is 3-4 times higher than those of other reported aqueous electrolyte-based supercapacitors and even comparable to that of commercial lithium ion batteries. The device also shows marginal capacitance degradation after 1000 cycles' bending test, demonstrating its potency in the application of flexible energy storage devices.

Key words: Asymmetric supercapacitor, High energy density, Flexible device, Three dimensional(3D), Fe2O3 compo-site anode