Ag nanoparticles decorated MnO2/reduced graphene oxide as advanced electrode materials for supercapacitors

A ternary nanocomposite of Ag/MnO2/RGO, in which reduced graphene oxide (RGO) sheets are decorated with Ag and MnO2 nanoparticles, is synthesized by in situ growth of MnO2 nanoparticles on graphene oxide (GO) sheets, following by co-reduction of Ag+ and GO. The in situ formed Ag and MnO2 nanoparticles with sizes of several nanometers are homogeneously distributed on the surface of RGO sheets. The composites as electrode materials for supercapacitors are investigated. It is found that the Ag/MnO2/RGO nanocomposites exhibit excellent capacitive performance with a specific capacitance as high as 467.5 F g(-1) at the scan rate of 5 mV s(-1), which is much higher than that of MnO2/RGO nanocomposites (293.2 F g-1). Moreover, the specific capacitance of Ag/MnO2/RGO does not show any obvious degeneration after 1000 cycles at the scan rate of 80 mV s(-1), indicating that the Ag/MnO2/RGO composites possess an excellent cycle life. The greatly enhanced capacitive performance of the Ag/MnO2/RGO nanocomposites is mainly attributed to the introduction of Ag nanoparticles, which can increase the electrical conductivities of the nanocomposites, and promote the electron transfer between the active components. This study suggests that graphene-based ternary nanocomposites are a promising class of electrode materials for high performance energy storage applications. (C) 2014 Elsevier B.V. All rights reserved.