High performance supercapacitors using metal oxide anchored graphene nanosheet electrodes

Metal oxide nanoparticles were chemically anchored onto graphene nanosheets (GNs) and the resultant composites—SnO2/GNs, MnO2/GNs and RuO2/GNs (58% of GNs loading)—coated over conductive carbon fabric substrates were successfully used as supercapacitor electrodes. The results showed that the incorporation of metal oxide nanoparticles improved the capacitive performance of GNs due to a combination of the effect of spacers and redox reactions. The specific capacitance values (with respect to the composite mass) obtained for SnO2/GNs (195 F g−1) and RuO2/GNs (365 F g−1) composites at a scan rate of 20 mV s−1 in the present study are the best ones reported to date for a two electrode configuration. The resultant supercapacitors also exhibited high values for maximum energy (27.6, 33.1 and 50.6 W h kg−1) and power densities (15.9, 20.4 and 31.2 kW kg−1) for SnO2/GNs, MnO2/GNs and RuO2/GNs respectively. These findings demonstrate the importance and great potential of metal oxide/GNs based composite coated carbon fabric in the development of high-performance energy-storage systems.