Preparation of Graphene/Polypyrrole Composite Film via Electrodeposition for Supercapacitors

Graphene/polypyrrole (PPy) composite film was prepared by simple electrodeposition of graphite oxide and pyrrole mixture under acid conditions. The morphology, composition, and electronic structure of the composites were characterized by using transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectrometer, X-ray diffraction, and X-ray photoelectron spectroscopy. Based on the fast redox property of PPy and high conductivity of graphene, the prepared composite film could be constructed to a supercapacitor device directly. The electrochemical performances of the supercapacitor were investigated by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The composites showed better electrochemical performances than the individual components. A high specific capacitance of 335 F·g
$^{-1}$
was obtained with the capacitance retention of 85% after 1000 cycles at a current density of 1 A·g
$^{-1}$
by charge–discharge analysis between 0 and +1.0 V. The enhanced specific capacitance and cycling life implied a synergistic effect of graphene and PPy.