One-pot Hydrothermal Synthesis of Novel NiCoO2/Reduced Graphene Oxide Composites for Supercapacitors

Novel NiCoO2/rGO composites with a structure of NiCoO2 nanoparticles anchored on layers of reduced graphene oxide（rGO） were synthesized via a simple one-pot hydrothermal method and were used as faradaic electrodes for supercapacitors. The microstructures of NiCoO2/rGO composites were characterized by means of field emission scanning electron microscopy（FESEM）, transmission electron microscopy（YEM）, X-ray diffraction（XRD） and thermogravimetric analysis（TGA）. When acting as faradaic electrodes for supercapacitors, NiCoO2/rCK） compo- sites exhibited a specific capacity of 288 C/g at the current density of 2 A/g and maintained 139.98 C/g at 20 A/g. High capacity retention ratios up to 88% could be achieved after 1000 cycles at a current density of 2 A/g. The out- standing cycling stability was primarily attributed to the combination of mixed transition metal oxides and rGO, which not only maintains a high electrical conductivity for the overall electrode but also prevents the aggregation and volume expansion of electrochemical materials during the cycling processes.

Abstract Novel NiCoO2/rGO composites with a structure of NiCoO2 nanoparticles anchored on layers of reduced graphene oxide（rGO） were synthesized via a simple one-pot hydrothermal method and were used as faradaic electrodes for supercapacitors. The microstructures of NiCoO2/rGO composites were characterized by means of field emission scanning electron microscopy（FESEM）, transmission electron microscopy（YEM）, X-ray diffraction（XRD） and thermogravimetric analysis（TGA）. When acting as faradaic electrodes for supercapacitors, NiCoO2/rCK） compo- sites exhibited a specific capacity of 288 C/g at the current density of 2 A/g and maintained 139.98 C/g at 20 A/g. High capacity retention ratios up to 88% could be achieved after 1000 cycles at a current density of 2 A/g. The out- standing cycling stability was primarily attributed to the combination of mixed transition metal oxides and rGO, which not only maintains a high electrical conductivity for the overall electrode but also prevents the aggregation and volume expansion of electrochemical materials during the cycling processes.