Studies on electrochemical properties of ZnO/CuMn₂O₄ NCs as electrode material for supercapacitor application

The current study involved a two-step process to create nanocomposites (NCs) of Zinc oxide (ZnO)/Copper manganite (CuMn₂O₄). Pure ZnO, CuMn₂O₄ nanoparticles, and ZnO/CuMn₂O₄ NCs were synthesized through co-precipitation and hydrothermal techniques. The Power X-ray Diffraction (PXRD) pattern indicates the existence of hexagonal wurtzite and spinel cubic phase structures of ZnO and CuMn₂O₄ in ZnO/CuMn₂O₄NCs. The appearance of three peaks at 542 cm⁻¹, 634 cm⁻¹, and 439 cm⁻¹ in ZnO/CuMn₂O₄ NCs can be attributed to the stretching and bending vibration bands of Mn–O, Cu–O, and Zn–O metal oxides as revealed by the FTIR studies. FESEM analysis revealed that the ZnO, CuMn₂O₄ and ZnO/CuMn₂O₄ NCs had a spherical morphology, while EDAX analysis identified the elemental composition of Zn, Cu, Mn, and O in the prepared materials. Cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements were used to investigate the electrochemical performance of the prepared material. According to the electrochemical findings, the ZnO/CuMn₂O₄ electrode exhibited Faradic behavior similar to that of a battery, and at a current density of 0.4 Ag⁻¹ in a 2 M KOH electrolyte, it recorded the highest specific capacitance value of 562.36 Fg⁻¹ compared to ZnO and CuMn₂O₄. Based on the observed results, prepared ZnO/CuMn₂O₄ NCs are well suited for ultrafast redox kinetics due to their improved ionic conductivity and electrochemical stability.