PVP-assisted hydrothermal synthesis of VO(OH)2 nanorods for supercapacitor electrode with excellent pseudocapacitance

Abstract

Vanadium oxyhydroxide VO(OH)2, which may possess specific chemical and physical properties, has been paid less attention comparing with vanadium oxides. Herein, with the assistance of polyvinyl pyrrolidone (PVP) and by adjusting pH about 4.7, VO(OH)2 was successfully synthesized by a facile hydrothermal method for the first time, which were short nanorods with widths of 50–130 nm and lengths of 250–500 nm. Electrochemical performance of VO(OH)2 nanorods was firstly investigated as supercapacitor electrodes, which were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). VO(OH)2 nanorods showed capacitive behavior based on pseudocapacitance and superior rate capability. Specific capacitance of 198 F·g−1 was achieved at 0.5 A·g−1. These findings suggested that VO(OH)2 nanorods can be promising candidate as potential material for supercapacitor electrode.