Abstract: Nanostructured Co3O4 with different morphologies was synthesized by solvothermal method using different cobalt salts in water and n-butanol solvent system. The structure and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electronmicroscopy (TEM). The results showed that the shape and size of Co3O4 could be controlled by altering the anions in the reaction system. Electrochemical properties of Co3O4 electrode were characterized by cyclic voltammetry (CV), galvanostatic charge/discharge and alternating current (AC) impedance method. The results indicated that the shape and size of Co3O4 had remarkable influence on its capacitive performance. In the potential range of -0.40-0.55 V(vs SCE), the spherical Co3O4 obtained from cobalt nitrate showed excellent capacitance performance in 2 mol·L -1 KOH electrolyte. The initial specific capacitance of single Co3O4 electrode reached 362.0 F·g-1 and 90% was maintained after 400 cycles.

Key words: Co3O4, Supercapacitor, Solvothermal method