Formation of high-performance Cu-WOx@C tribasic composite electrode for aqueous symmetric supercapacitor

Abstract

Currently, advanced electrode materials have excellent potential in energy storage as the result of their high specific surface area and strong electron and ion transport capacity. Herein, a tribasic composite material Cu-WOx@C is obtained by calcining {PW12O40}@metal-organic frameworks under the protection of nitrogen, which is the first time to use this way to synthesize tribasic tungsten oxide. The Cu-WOx@C electrode displays excellent electrochemical properties with the ultrahigh specific capacitance of Cu-WOx@C is 4531 F g−1, which is much better than 2361 F g−1 of {PW12O40}@metal-organic frameworks precursor at a current density of 4.3 A g−1, and also the highest in the recorded tungsten-based materials. The Cu-WOx@C exhibits remarkable cycling stability (93% after 5000 cycles) at a high current density of 22 A g−1. The fabricate aqueous symmetric supercapacitor by using Cu-WOx@C electrode exhibited a wide voltage of 1.8 V with a maximum energy density of 229 Wh kg−1 and a maximum power density of 11.9 kW kg−1 in 1 M H2SO4 electrolyte. These properties show that Cu-WOx@C is likely to be a next-generation of alternative electrode material for using in practical application.