Synthesis of long chain-like nickel cobalt oxide nanoneedles–reduced graphene oxide composite material for high-performance supercapacitors

Long chain-like nickel cobalt oxide nanoneedle–reduced graphene oxide (NiCo2O4–rGO) composite materials were synthesized via a one-step hydrothermal method. The optimized mass ratio (NiCo2O4 to rGO) was defined. The electrochemical results showed NiCo2O4–rGO to possess remarkable electrochemical performance, i.e. high specific capacitance of 882 F g−1 at a current density of 1 A g−1 and good rate capability 610 F g−1 at 10 A g−1. It is noteworthy that the specific capacitance increased instead of decreasing up to 800 cycles, and only 6.2% was lost after 3000 cycles compared to the highest specific capacitance at 800 cycles. For their high specific capacitance, remarkable rate capability and excellent cycle stability, NiCo2O4–rGO composite materials show great potential in the application of supercapacitors.