Substrate driven growth of quaternary CoNiCuZn oxide nanostructures via electrodeposition for enhanced supercapacitor applications

Abstract The escalating global energy demand necessitates the development of efficient, sustainable, and robust energy storage solutions. Supercapacitors, bridging the gap between conventional capacitors and batteries, have attracted significant attention due to their high-power density, fast charge–discharge capability, and long cycle life. In this study, a novel approach was employed for the direct growth of mixed quaternary metal oxides (QMOs) comprising cobalt, nickel, copper, and zinc on various conductive substrates, including carbon cloth, stainless steel mesh, and nickel foam, using an electrodeposition method. The fabricated hierarchical 3D nanostructures were systematically characterized to evaluate their electrochemical performance. The CoNiCuZn oxide electrode exhibited outstanding capacitive behavior, achieving specific capacitances of 885.13 F/g, 2965.91 F/g, and 3824.34 F/g at 5mV/s. Specific capacity for carbon cloth, SS mesh, and Ni foam as 288 mAh/g, 908.33 mAh/g, and 2078.33 mAh/g, respectively, at 5mV/s, with capacitance retention of 80%, 89%, and 94% after 2500 cycles. The symmetric CoNiCuZn oxide/CoNiCuZn oxide device delivers an energy density of 14.32 Wh/kg at 1.36 kW/kg with 60.27% capacitance retention, supported by low Rs and Rct values. These results confirm excellent rate capability, stability, and strong potential for practical supercapacitor applications. These findings highlight the potential of mixed quaternary metal oxides as cost-effective and eco-friendly electrode materials for the next generation of flexible, high-performance supercapacitors.