3D hierarchical cobalt vanadate nanosheet arrays on Ni foam coupled with redox additive for enhanced supercapacitor performance.

Abstract

Room-temperature synthesized 3D hierarchical cobalt vanadate (Co3V2O8) nanosheet arrays on Ni foam for use as supercapacitor electrode is presented. In a 3 M KOH electrolyte, the electrode exhibits a capacitance of 109.9 mA h g-1 (878.9 F g-1) at a current density of 1 A g-1. The capacitance is enhanced to 198.1 mA h g-1 (1584.5 F g-1) at 1 A g-1 through the addition of 0.05 M redox-additive K3[Fe(CN)6] into the KOH electrolyte. Furthermore, the Co3V2O8/activated carbon asymmetric supercapacitor cell with the advanced electrolyte outperforms most reported Co3V2O8-based electrodes with a remarkable energy density of 55.5 W h kg-1 at an 800 W kg-1 power density. Combining a facile synthetic strategy and excellent electrochemical performance, the obtained Co3V2O8 exhibits potential for practical application.