Optimized NiCo₂O₄/rGO hybrid nanostructures on carbon fiber as an electrode for asymmetric supercapacitors

The NiCo₂O₄ nanowires and reduced graphene oxide (rGO) hybrid nanostructure has been constructed on carbon fibers (NiCo₂O₄/rGO/CF) via a hydrothermal method. The effects of graphene oxide (GO) concentration on the structure and performance of the NiCo₂O₄/rGO/CF were investigated in detail to obtain the optimized electrode. When the GO concentration was 0.4 mg ml^-1, the rGO/NiCo₂O₄/CF composite exhibited a maximum specific capacitance of 931.7 F g^-1 at 1 A g^-1, while that of NiCo₂O₄/CF was 704.9 F g^-1. Furthermore, the NiCo₂O₄/rGO/CF//AC asymmetric supercapacitor with a maximum specific capacitance of 61.2 F g^-1 at 1 A g^-1 was fabricated, which delivered a maximum energy density (24.6 W h kg^-1) and a maximum power density (8477.7 W kg^-1). Results suggested that the NiCo₂O₄/rGO/CF composite would be a desirable electrode for flexible supercapacitors.