Rational Construction of V2O5@rGO with Enhanced Pseudocapacitive Storage for High‐Performance Flexible Energy Storage Device

Abstract

AbstractEnormous efforts have recently been devoted to exploiting high Faradaic redox active materials with ultrahigh energy density in new generation energy storage systems. In this study, a facile and cost‐effective solvothermal method was employed to synthesize high capacitance of rGO in situ encapsulating V2O5 microspheres (note as VrG). Benefiting from its unique hierarchical structure, large number of Faradaic redox active sites, and excellent electronic conductivity of rGO, the VrG composites can provide excellent pseudocapacitive performance with fast charge transfer and reaction kinetics between electrolyte and electrode material. Especially, the post‐optimized VrG‐5 demonstrates a remarkable discharge specific capacitance of 575 C g−1 at a current density of 1 A g−1 and an outstanding rate capability (48 % capacitance retention with the rate increasing 20 times), which is far better than the precursor component V2O5 under identical conditions. More importantly, the flexible VrG‐5//rGO asymmetric supercapacitors device can not only deliver excellent specific capacitance of 237 C g−1 and a high energy density of 46 Wh Kg−1, but also exhibit a superior mechanical flexibility under various bending angles and even 83 % capacitance retention after 5000 cycles under mechanical bending 180°, indicating its great potential application in the future flexible energy storage devices.