Enhancing the Electrochemical Efficiency of ZnO/NiO Nano Composite Through Air Plasma Treatment

Abstract

This investigation examines the electrochemical behaviors of ZnO/NiO nanocomposites synthesized through a hydrothermal method and subsequently subjected to air plasma treatment, highlighting their potential in energy storage applications. XRD analysis confirmed the highly crystalline nature of the wurtzite ZnO and cubic NiO phases without secondary impurities. Plasma treatment enhanced crystallinity, as evidenced by sharper diffraction peaks. FTIR analysis revealed improvements in oxygenated functional groups posttreatment. FESEM images showed uniform spherical structures (∼2 µm) with increased surface roughness, and EDAX confirmed the elemental composition. Electrochemical analysis revealed significant improvements in performance due to plasma treatment. The plasma treated ZnO/NiO exhibited a total capacitance of 4773 F/g, compared to 2773 F/g for untreated samples. Specific capacitance at 10 mV/s decreased from 829 F/g (untreated) to 691 F/g (treated); however, at 100 mV/s, the treated sample retained a higher capacitance (331 F/g) than the untreated (187 F/g). A higher b-value (0.742) for treated samples indicates the enhanced capacitive behavior. Charge-discharge studies demonstrated high reversibility, with treated samples achieving better nonlinear double layer characteristics. Impedance spectroscopy showed reduced polarization and charge transfer resistance for treated samples compared to untreated, indicating improved conductivity and active site availability. These outcomes spotlight the effectiveness of the plasma treatment of ZnO/NiO nanocomposites.