Design and synthesis of N-doped mesoporous carbon@ NiCo 2 O 4 nanocomposites with various morphologies for high electrochemical performance applied in supercapacitors

Abstract Hybrid nanostructures of N-doped mesoporous carbon@NiCo2O4 with controllable compositions are prepared by a facile hydrothermal method. Various morphologies of N-doped mesoporous carbon@NiCo2O4 are successfully synthesized including sea urchins-like structure of free NiCo2O4, litchi chinensis-like structure of NC-100@ NiCo2O4 and waxberry-like structure of NC-200@ NiCo2O4. All samples exhibit excellent rate capability and cycle stability. The incorporation of N-doped mesoporous carbon causes a dominant capacitance increase. Free NiCo2O4 only possesses a specific capacitance of 1038 F g−1 at 1 A g−1, while NC-200@ NiCo2O4 renders a much higher specific capacitance of 1624 F g−1, which shows a distinct improvement of 56.4%. Moreover, NC-200@ NiCo2O4 still performs a high specific capacitance of 1360 F g-1 even at a high current density of 10 A g−1. Besides, the final capacitance can still maintain 94.3% of the initial capacitance even after 10,000 cycles.