Capacitance properties of poly(3,4-ethylenedioxythiophene)/polypyrrole composites

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 electrochemical capacitance properties were investigated with cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) techniques with two- or three-electrode cell configuration. The data showed that the specific capacitance of composite electrodes, due to the synergic effect of poly(3,4-ethylenedioxythiophene) (PEDOT) and PPy, is much higher than the values of either pure PEDOT or pure PPy electrodes. Moreover, the composites prepared on the surface of PPy with horn-like structure allow the specific capacitance up to more than 200 F g−1 and have a good cycleability. This implies that PEDOT/PPy composites are promising to be used as electrode material of supercapacitors.