Study of spinel ZnNixMnxCo2-2xO4 (x = 0, 0.25, 0.5, 0.75, and 1.0) nanomaterials for supercapacitor electrode applications by hydrothermal synthesis

This research investigated the properties and performance of spinel ZnNixMnxCo2-2xO4 for use as a supercapacitor electrode. All materials employed a single-step hydrothermal procedure to synthesize. The stoichiometric values of x = 0, 0.25, 0.50, 0.75, and 1.0 were studied. Various characterized methods, e.g., XRD, SEM, and XPS, were utilized for material characterization. The electrode properties were assessed with a 2 M KOH electrolyte as the testing medium. For the electrochemical studies in this work, cyclic voltammetry (CV) was used to analyze the type of material being a supercapacitor, where the result indicated the spinel ZnNixMnxCo2-2xO4 exhibited the pseudocapacitor type. Furthermore, the charging and discharging of the supercapacitor were employed to examine the absorption and desorption of charges at the charging and discharging process, respectively. The internal resistance of the electrode, which affects the supercapacitor’s efficiency, was evaluated using electrochemical impedance spectroscopy (EIS). Among those CV studies, the electrode made from the ZnNi0.75Mn0.75Co0.5O4 material showed the best supercapacitor property, demonstrating a capacitance of 535 F/g at 5 mV/s scan rate.