Co3O4/carbon nano-onions composite as supercapacitor electrode and its excellent electrochemical performance

An ionic liquid derived Co3O4/carbon nano-onions composite has been prepared by carbothermal reduction followed by oxidation. The introduction of carbon nano-onions improves the conductivity and structural stability of Co3O4 electrode material. Electrochemical measurements indicate that the redox reversibility is significantly improved. The Co3O4/carbon nano-onions composite shows a large specific capacitance of 402.35 F g(-1) at a current density of 0.5 A g(-1). After 9000 cycles, the specific capacitance retention remained 76 % at 1 A g(-1). The as-prepared Co3O4/carbon nano-onions composite delivers superior capacitive performance with good rate capability, large specific capacitance, and excellent cyclic performance, showing great application potential for high-performance electrochemical supercapacitors.