Synthesis and Characterization of CuO Nanostructures via Wet-Chemical Route for Supercapacitor Applications

We have demonstrated the superior electrochemical properties of copper oxide (CuO) with a monoclinic structure and nanoflower morphology, synthesized using the sol–gel and wet chemical routes, with copper foil as the substrate. The prepared nanostructures have been characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. The XRD results confirm the monoclinic structure of the CuO nanostructures and the SEM analysis reveals nanoflower formation via the wet chemical route, while the sol–gel route produces bulk morphology. We have found that the unique combination of a monoclinic structure and nanoflower morphology is advantageous for use as a promising electrode material in supercapacitor applications. The electrochemical properties in three electrode system using the obtained nanostructures have been investigated through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 6.0 M KOH electrolyte. The CuO nanostructured electrode material prepared via the wet chemical route (Sample 3) demonstrates a maximum specific capacitance of 453 F/g at a scan rate of 2 mV/s. These results indicate that CuO is a potential electrode material for supercapacitor applications.