High-performance ZnO–CuSe nanocomposites as advanced electrode materials for energy storage applications

Currently, energy storage devices face challenges in capacity, energy density, and durability. This study develops a high-performance asymmetric supercapacitor by synthesizing novel ZnO-CuSe nanocomposites through wet-chemical methods to enhance these properties. The ZnO-CuSe nanocomposite exhibits optimized electrochemical performance, as demonstrated by its capacitive behavior and active redox reactions. Enhanced electrochemical properties are attributed to a superior bounded loop area in cyclic voltammetry, greater current response, and prolonged discharge duration. The ZnO-CuSe nanocomposite electrode achieved a specific capacitance of 863 F/g at 1 A/g. Furthermore, the synergistic interaction between the pseudocapacitive materials results in reduced resistance, as observed in the impedance analysis, compared to individual ZnO and CuSe electrodes. The ZnO-CuSe||AC||KOH supercapacitor exhibited impressive stability, maintaining 90.4% of its capacity after 5000 charge-discharge cycles at the maximum current. It achieved a prominent specific capacitance of 151 F/g, an energy density of 53.8 Wh/kg and a power output of 4044 W/kg, when the voltage limit was increased to 1.6 V in an aqueous electrolyte. This research demonstrates the capability of the ZnO-CuSe nanocomposite as an emerging material with great potential for enhancing the electrochemical performance for potential eco-friendly energy storage technologies.