Optimized NiCo(2)O(4)/rGO hybrid nanostructures on carbon fiber as an electrode for asymmetric supercapacitors

The NiCo(2)O(4) nanowires and reduced graphene oxide (rGO) hybrid nanostructure has been constructed on carbon fibers (NiCo(2)O(4)/rGO/CF) via a hydrothermal method. The effects of graphene oxide (GO) concentration on the structure and performance of the NiCo(2)O(4)/rGO/CF were investigated in detail to obtain the optimized electrode. When the GO concentration was 0.4 mg ml(−1), the rGO/NiCo(2)O(4)/CF composite exhibited a maximum specific capacitance of 931.7 F g(−1) at 1 A g(−1), while that of NiCo(2)O(4)/CF was 704.9 F g(−1). Furthermore, the NiCo(2)O(4)/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 NiCo(2)O(4)/rGO/CF composite would be a desirable electrode for flexible supercapacitors.