▎ 摘　　要

NOVELTY - Preparing cobalt tetroxide composite material rich in oxygen vacancies involves providing a polydopamine-reduced graphene suspension at concentration of 0.5-5 mgL-1. Cobalt salt and precipitating agent are added to the polydopamine-reduced graphene suspension, mixed well, and a hydrothermal reaction is performed at 120-200 degrees C for 4-12 hours, after the reaction is over, and calcinated in a nitrogen or inert gas atmosphere at 330-380 degrees C for 1.5-2.5 hours to obtain a cobalt tetroxide composite material. USE - Method for preparing cobalt tetroxide composite material that is utilized as electrode material in a supercapacitor (claimed). ADVANTAGE - The material has good electrochemical performance in potassium hydroxide electrolyte, good rate performance and excellent cycle stability, and achieves excellent specific capacitance of 1562 Fg-1 in a three-electrode system under the condition of a current density of 0.5 Ag-1.