Preparation of High-capacity Carbon-coated Nickel Cobaltate Hollow Nanospheres Electrode for supercapacitors

NiCo 2 O 4 is a binary transition metal oxide with a spinel structure. It has higher theoretical specific capacitance, good cycle stability, lower cost, and environmental friendliness. In this paper, hollow silica microspheres were prepared by using carbon dioxide microspheres as templates. The physical characterization results of the materials show that the prepared nanospheres have a good hollow spherical structure. After the carbon coating, a very obvious carbon particle layer grows on the surface of the hollow sphere. Electrochemical test results show that the rate performance and cycle stability of the carbon-coated nickel cobaltate hollow microspheres have been significantly improved, and the charge transfer resistance has been significantly reduced. The specific capacitance reaches 637.5 F/g at a current density of 0.5 A/g. When the current density is changed from 0.5 A/g to 5 A/g, the capacitance retention is as high as 90.2%. At a current density of 5 A/g, the carbon-coated nickel cobaltate hollow microspheres can maintain a specific capacitance of 91.7% after 2000 charge and discharge cycles.