▎ 摘　　要

In this study, a novel high-performance electrode material based on MnO2 nanoparticles coated onto recently discovered 2-D graphene nanoplatelets was fabricated by a hydrothermal method be used as composite for supercapacitor electrode. The maximum capacitance and energy density obtained for this nanocomposite were 542 F/g and 75.3 Wh/kg at a scan rate of 0.01 V/s in 2 M KCl. These impressive results were attributed to a synergistic effect between GNPs and MnO2 which combine the remarkable electrical conductivity of GNPs with the high pseudocapacitance of the MnO2 nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.