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

Room-temperature synthesized 3D hierarchical cobalt vanadate (Co(3)V(2)O(8)) 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 K(3)[Fe(CN)(6)] into the KOH electrolyte. Furthermore, the Co(3)V(2)O(8)/activated carbon asymmetric supercapacitor cell with the advanced electrolyte outperforms most reported Co(3)V(2)O(8)-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 Co(3)V(2)O(8) exhibits potential for practical application.