Graphene/vanadium oxide hybrid electrodes for electrochemical capacitor

Graphene/vanadium oxide (RG/VOx center dot nH(2)O) hybrid electrodes with different graphene (RG) amounts were prepared by one-step simultaneous hydrothermal-reduction technology in a suspension of NH4VO3, NH2CSNH2 and graphite oxide (GO) nanosheets. The hydrothermal treatment made the reduction of GO to RG and the formation of VOx center dot nH(2)O nanoplates. The graphene nanolayers were dispensed on the surface of VOx center dot nH(2)O nanoplates, and further intimated contact between the RG nanosheets and VOx center dot nH(2)O nanoplates, which caused the mesoporous structure derived from the self-assembly between RG nanosheets and VOx center dot nH(2)O nanoplates and the high active utilization of VOx center dot nH(2)O. The vanadium was existed in a mixed valance, and some V (V) could be reduced into V (IV) by the carbon on the graphene nanosheets. An obviously synergistic effect was existed between VOx center dot nH(2)O nanoplates and GR nanosheets. RG (0.5)/VOx center dot nH(2)O electrode with RG content of 10 wt% exhibited not only high specific capacitance of 384 Fg(-1) at a scan rate of 5 mV s(-1) in 0.5 mol L-1 K2SO4 electrolyte, but also relatively good cycle stability at a current density of 5 A g(-1) (60% capacitance retention after 1000 cycles), which made it has a potential application as a supercapacitor electrode material. (C) 2014 Elsevier B.V. All rights reserved.