Enhanced capacitance and rate capability of graphene/polypyrrole composite as electrode material for supercapacitors

Graphene and polypyrrole composite (PPy/GNS) is synthesized via in situ polymerization of pyrrole monomer in the presence of graphene under acid conditions. The structure and morphology of the composite are characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectrometer (FTIR), X-rays photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). It is found that a uniform composite is formed with polypyrrole being homogeneously surrounded by graphene nanosheets (GNS). The composite is a promising candidate for supercapacitors to have higher specific capacitance, better rate capability and cycling stability than those of pure polypyrrole. The specific capacitance of PPy/GNS composite based on the three-electrode cell configuration is as high as 482 F g(-1) at a current density of 0.5 A g(-1). After 1000 cycles, the attenuation of the specific capacitance is less than 5%, indicating that composite has excellent cycling performance. (C) 2011 Elsevier B.V. All rights reserved.