Octahedral CoO with nanostructures decorated with Ag nanoparticles was prepared via a facile solvothermal approach.After being annealed at 500 ℃ for 1 h,an electrochemical capacitor material of Co3O4 decorated with Ag2O was obtained.The cyclic voltammetry and galvanostatic charge-discharge were used to evaluate the electrochemical properties of the as-prepared products.The results indicated that the as-prepared samples exhibited fine pseudo-capacitive performance,and the surface modifications of Ag2O can significantly increase the capacitance of the Co3O4 material.The specific capacitance of Ag2O/Co3O4 composite electrode was up to 217.6 F·g-1,which was 3.35 times as high as that of pure Co3O4.Moreover,Ag2O/Co3O4 composite showed an excellent cycle performance,and 65.3％ of specific capacitance was maintained after 200 cycles.