▎ 摘　　要

Graphene/polypyrrole nanocomposites were prepared by in situ oxidative polymerization method by varying the weight percentage of graphene. FTIR study confirmed the formation of polypyrrole in presence of graphene. Field Emission Scanning Electron Microscopy (FESEM) and High Resolution Transmission Electron Microscopy (HRTEM) were used to characterize the morphology of the nanocomposites which showed a uniform coating of graphene with the polypyrrole. From the cyclic voltammetry (CV) measurement it was found that the capacitances of the nanocomposites were increased up to a certain percentage of graphene and after which it showed a downward trend. The maximum capacitance value and energy density, among the composites studied, were found to be 409 F/g and 227.2 Wh/Kg at 10 mV/s scan rate. However, maximum power density achieved was 4617 W/kg at a scan rate of 200 mV/s. (C) 2011 Elsevier B.V. All rights reserved.