Abstract: Pure polyhedral Co₃O₄ particles were synthesized simply with cobalt chloride solution as the raw material by a spray-oxidation method under oxygen-enriched conditions.The feed solution prepared by using CoCl₂·6H₂O was sprayed with an air-nozzle and oxidized in the pipe high-temperature resistance furnace with compressed oxygen-enriched air as the carrier gas.The as-prepared products were characterized by X-ray diffraction analysis(XRD),Fourier-transform infrared spectroscopy(FT-IR) and scanning electron microscopy (SEM). The experimental results show that pure polyhedral Co₃O₄ particles are prepared successfully at the feedsolution concentration of 2.0 rnol·L ^-1, flow rate of 6.0 L· h^-1 reaction temperature of 800℃, and spray pressure of 0.1 MPa. The electrochemical capacitive properties of the Co₃O₄ particles were evaluated using cyclic voltammetry and alternating current impedance methods. The capacitive properties depict that the sample Co₃O₄ by the spray-oxidation method is capable of exhibiting excellent capacitive performance in the 5.0 mol· L^-1 KOH electrolyte.