Electrochemical supercapacitor electrode material based on poly(3,4-ethylenedioxythiophene)/polypyrrole composite

Abstract

Poly (3,4-ethylenedioxythiophene)/polypyrrole composite electrodes were prepared by electropolymerization of 3,4-ethylenedioxythiophene (EDOT) on the surface of polypyrrole (PPy) modified tantalum electrodes. The morphology observation of PPy and poly(3,4-ethylenedioxythiophene)/polypyrrole composite (PEDOT/PPy) was performed on Field Emission Scanning Electron Microscope (SEM). The electrochemical capacitance properties of the composite were investigated with cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) techniques in the two- or three-electrode cell system. The results show that the PEDOT/h-PPy (PPy with horn-like structure) composite films were characterized with highly porous structure, which leads to their specific capacitance as 230 Fg −1 in 1 M LiClO 4 aqueous solutions and even 290 Fg −1 in 1 M KCl aqueous solutions. Moreover, the composite exhibits a rectangle-like shape of voltammetry characteristics even at scanning rate 100 mV s −1, a linear variation of the voltage with respect to time without a clear ohm-drop phenomenon in galvanostatic charge–discharge process and almost ideal capacitance behavior in low-frequency in 1 M KCl solutions. Furthermore, specific power of the composite would reach 13 kW kg −1 and it had good cycle stability. All of the above imply that the PEDOT/h-PPy composites were an ideal electrode material of supercapacitor.