Copper oxide-based high-performance symmetric flexible supercapacitor: potentiodynamic deposition

Flexible supercapacitors have gained significant attention in recent times due to their many advantages such as high specific capacitance, lightweight, long lifespan, high energy density, high flexibility, and high-power density. These benefits make them ideal for various high-power applications in various industries. Copper oxide is particularly attractive as an electrode material because of its high theoretical specific capacitance, low cost, and eco-friendliness. Copper oxide is the most promising electrode material in energy storage systems among metal oxides due to its higher theoretical value of specific capacitance (1800 F/g). In the present study, the synthesis of a thin film of copper oxide on a flexible copper substrate through electrodeposition was carried out to produce a flexible and lightweight supercapacitor. The supercapacitor's performance was evaluated using cyclic voltammetry (CV) and galvanostatic charge–discharge analysis in a 1 M KOH electrolyte. The results showed that the copper oxide/copper-based supercapacitor had a large specific capacitance of 983.3 F/g and good performance even after 2200 cycles, with a capacity retention of 89.70%. The flexibility of the electrode was measured at various bending angles. The electrode showed a capacity retention of 87.5% after a 180° bending angle with a good coulombic efficiency of 79.15%. Hence, it could be a promising material for flexible supercapacitor electrodes. This demonstrates that copper oxide has great potential as a material for flexible supercapacitor electrodes. The newer applications for supercapacitors in industries such as wearable electronics, flexible displays, and energy harvesting systems can be explored.