Electrodeposition and pseudocapacitive properties of tungsten oxide/polyaniline composite

Abstract

Composite films of tungsten oxide (WO3) and polyaniline (PANI) have been electrodeposited by cyclic voltammetry in a mixed solution of aniline and precursor of tungsten oxide. Surface morphology and chemical composition of WO3/PANI composite are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The influence of H2O2 on the electrodeposition of WO3/PANI composite film is also investigated. Cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS) results show that WO3/PANI composite film exhibit good pseudocapacitive performance over a wide potential range of −0.5 to 0.7V vs. SCE with the specific capacitance of 168Fg−1 at current density of 1.28mAcm−2 and energy density of 33.6Whkg−1, which is 91% higher than that of similarly prepared PANI (17.6Whkg−1). An asymmetric model capacitor using WO3/PANI as negative and PANI as positive electrodes over voltage range of 1.2V displays a specific capacitance of 48.6Fg−1 and energy density of 9.72Whkg−1 at the power density of 53Wkg−1, which is two times higher than that of a symmetric capacitor modeled by using two PANI films as both positive and negative electrodes.