Self-doped polyaniline/molybdenum oxide composite nanorods for supercapacitors

Abstract

A composite film of self-doped polyaniline and molybdenum oxide (SPAN/MoO_x) was prepared through multi-potential steps, in which the working electrode was held alternately at −0.7 and 1.2 V. The as-prepared composite was characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrophotometry (FTIR). Its surface morphologies were investigated by scanning electron microscopy (SEM). The supercapacitive performance of the composite film was investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). The SPAN/MoO_x displayed electroactivities in a large potential window from −0.8 to 1.0 V, showing the combined electroactivities of SPAN and MoO_x in the composite. The SPAN/MoO_x displayed a specific capacitance of 570 F g⁻¹ at a current density of 1.7 A g⁻¹, which is higher than those of similarly prepared SPAN (408 F g⁻¹) and MoO_x (100 F g⁻¹). The symmetric supercapacitor assembled using SPAN/MoO_x as both electrodes showed good rate behavior with an energy density of 35 W h kg⁻¹ at a high power density of 4.7 kW kg⁻¹.