Facile hydrothermally grown CuO/Co₃O₄ nanocomposite as an effective electrode material for enhanced supercapacitor applications

In this study, we developed a transition metal oxide based CuO/Co3O4 nanocomposites (NCs) by a facile hydrothermal method and the synthesized samples have been used as electroactive material for supercapacitor applications. The as-synthesized CuO/Co3O4 NCs were characterized by various techniques such as XRD, FESEM, XPS, etc. FESEM shows the uniform morphology of CuO/Co3O4 (1:3) NCs. Powder XRD confirms the formation of CuO/Co3O4 NCs without any impurities. XPS revealed the chemical state of metallic species. The electrochemical properties studied by CV, GCD and EIS analysis, confirms the pseudocapacitive behaviour with high specific capacitance at low scan rate. The FESEM image of CuO/Co3O4 NCs shows mixture of two different morphologies, spherical and cubical. These specific morphologies provide more active sites for electrochemical redox reactions. For comparison, CuO/Co3O4 NCs with different molar ratios were prepared and electrochemical properties were also analysed. The synergistic effect between metal oxides has enhanced the specific capacity of the nanocomposite. Electrochemical investigation of the synthesized samples and the influence of the molar ratios of CuO to Co3O4 in the composites were examined. The electrode of CuO/Co3O4 NCs exhibited high specific capacitance of 860 F/g at a current density of 2 A/g, which is higher than the previous reports in hydrothermal method. These results highlighted that the outstanding electrochemical performance of CuO/Co3O4 NCs, can be considered as a promising electrode material for electrochemical energy storage supercapacitors.