Abstract

Here we report a new strategy to improve the electrochemical stability of vanadium oxide electrodes for pseudocapacitors. Vanadium oxides are known to suffer from severe capacitance loss during charging/discharging cycling, due to chemical dissolution and ion intercalation/deintercalation-induced material pulverization. We demonstrate that these two issues can be addressed by using a neutral pH LiCl/PVA gel electrolyte. The function of the gel electrolyte is twofold: (i) it reduces the chemical dissolution of amphoteric vanadium oxides by minimizing water content and providing a neutral pH medium and (ii) it serves as a matrix to maintain the vanadium oxide nanowire network structure. Vanadium oxide nanowire pseudocapacitors with gel electrolyte exhibit excellent capacitance retention rates of more than 85% after cycling for 5000 cycles, without sacrificing the electrochemical performance of vanadium oxides.