Cobalt oxide (Co3O4)/graphene nanosheets (GNS) composite prepared by novel route for supercapacitor application
Cobalt oxide (Co3O4)–graphene nanosheets (GNS) composite was prepared using a novel route. Room temperature prepared graphite oxide was exfoliated at low temperature and subsequently reduced to GNS by chemical method. Successful compound formation was confirmed and structural details were obtained from XRD studies. Cobalt oxide was found to crystallize in spinel fcc structure with average crystallite size of 9 nm in the composite. FTIR and XPS study confirms the removal of oxygen containing functional group in reduced graphene and spinel formation of cobalt oxide in the composite. Raman spectra depict the reestablishment of sp2 conjugated network of carbon atoms, on reduction to graphene. FESEM images reveal the nanosheet like morphology of the graphene being retained in the composite and promoting ion diffusion channels. Electrochemical characterization discloses the pseudocapacitive behaviour of the composite material. Higher specific capacitance of 650 F/g was exhibited by GNS–Co3O4 at 5 mV/s scan rate. Symmetrical supercapacitor fabricated using GNS–Co3O4 demonstrated superior power characteristics. Graphene in the composite has substantially increased the electron and ion transport in the electrode material leading to enhanced performance.
KeywordsGraphene Oxide Co3O4 Cobalt Oxide Graphite Oxide Cyclic Voltammetry Curve
Financial support from Anna University by providing Anna Centenary Research Fellowship (ACRF) for A. Nirmalesh Naveen is highly appreciated (Lr. No. CR/ACRF/2013/37).
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