▎ 摘　　要

new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/ PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by different electrochemical methods including cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance spectroscopy (EIS) in 0.5 M Na2SO4 solution. Remarkably, V2O5/PPy/GO nanocomposite shows a specific capacitance of 750 F g(-1) at a current density of 5 A g(-1), which is far better than PPy (59.5 F g(-1)), V2O5/PPy (81.5 F g(-1)) and PPy/GO (344.5 F g(-1)). Furthermore, V2O5/PPy/GO maintains 83% of its initial value after 3000 cycles, which demonstrates good electrochemical stability of the electrode during repeated cycling. These results demonstrate that the combination of electrical double layer capacitance of GO and pseudocapacitive behavior of the PPy and V2O5 can effectively increase the specific capacitance and cycling stability of the prepared electrode. Also, a symmetric supercapacitor device assembled by V2O5/PPy/GO nanocomposite yielded a maximum energy density of 27.6 W h kg(-1) at a power density of 3600 W kg(-1), and a maximum power density of 13680 W kg(-1) at an energy density of 22.8 W h kg(-1). (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.