Preparation of reduced graphene oxide/cobalt oxide composites and their enhanced capacitive behaviors by homogeneous incorporation of reduced graphene oxide sheets in cobalt oxide matrix

Abstract: Incorporation of reduced graphene oxide (rGO) in Co3O4 matrix is systematically investigated through a chemical route for supercapacitors. The α-Co(OH)2 supported by graphene oxide is first fabricated by a chemical precipitation approach. Thermal decompositions of these precursors at the given temperature (150°C) lead to rGO/Co3O4 composites. Measurement results show that the morphology and electrochemical activity of the rGO/Co3O4 composites are influenced significantly by the mass ratios of rGO to Co3O4. When used as electrode materials in supercapacitors, the composite with mass ratio of 0.22:1 (rGO:Co3O4) achieves the specific capacitance as high as 291Fg−1 at 1Ag−1 in the potential range of −0.4 to 0.55V, as compared with each individual counterpart (56 and 161Fg−1 for rGO and Co3O4, respectively). In addition, the excellent rate capability and well cycling ability are observed in the composite electrodes. The enhanced electrochemical performance is indicative of a positive synergistic effect between rGO and Co3O4. These results suggest the importance and great potential of graphene based composites in the development of high-performance energy-storage systems. [Copyright &y& Elsevier]