Design and synthesis of hierarchical mesoporous WO3-MnO2 composite nanostructures on carbon cloth for high-performance supercapacitors

Abstract

Abstract To enhance the energy density and power performance of supercapacitors, the rational design and synthesis of active electrode materials with hierarchical mesoporous structure is highly desired. In the present work, fabrication of high-performance hierarchical mesoporous WO3-MnO2 composite nanostructures on carbon cloth substrate via a facile hydrothermal method is reported. By varying the content of MnO2 in the composite, different WO3-MnO2 composite thin films are obtained. The formation of composite is confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The Brunauer-Emmett-Teller (BET) analysis reveals maximum specific surface area of 153 m2 g−1. The optimized WO3-MnO2 composite electrode demonstrates remarkable electrochemical performance with high specific capacitance of 657 F g−1 at a scan rate of 5 mV s−1 and superior longterm cycling stability (92% capacity retention over 2000 CV cycles). Furthermore, symmetric flexible solid-state supercapacitor based on WO3-MnO2 electrodes has been fabricated. The device exhibits good electrochemical performance with maximum specific capacitance of 78 F g−1 at a scan rate of 5 mV s−1 and specific energy of 10.8 Wh kg−1 at a specific power of 0.65 kW kg−1. The improved electrochemical performance could be ascribed to the unique combination of multivalence WO3 and MnO2 nanostructures and synergistic effect between them