Facile nanoengineering of Co3O4@ZIF-8, MnO2@ZIF-8 and Co3O4@MnO2@ZIF-8 composite electrodes for supercapacitor application

In this current research, the hydrothermal, co-precipitation, and drop-casting approaches were effectively combined to synthesize composite nanostructures of Cobalt Oxide (Co3O4), Manganese Oxide (MnO2), and Zeolitic Imidazolate Frameworks (ZIF-8) electrodes for use in supercapacitors for energy storage. The study aims to enhance the electrochemical performances of Co3O4@ZIF-8, MnO2@ZIF-8 and Co3O4@MnO2@ZIF-8 composite electrodes for supercapacitor applications. The electrodes’ enhanced performances were influenced by the composite's structure, synthesis method, and the individual properties of Co3O4, MnO2, and ZIF-8. The research aimed to demonstrate that high specific capacitance, high energy density, high power density, and excellent electrochemical performance can be achieved by carefully regulating these variables. The field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and UV–visible spectroscopy were employed to study the nanostructures' morphology, crystallinity, and optical features, respectively, while the Fourier transform infra-red spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) were engaged to determine the functional groups and elemental compositions of various nanostructures. The peak specific capacitances of 1008, 1228 and 1435 Fg−1 are produced via cyclic voltammetry studies with a scan rate of 1.0 mVs−1 for Co3O4@ZIF-8 (CZ), MnO2@ZIF-8 (MZ) and Co3O4@MnO2@ZIF-8 (CMZ) electrodes, respectively. However, at 0.5 Ag−1 current density, the GCDs provide an optimal specific capacitance of 1388, 1524, and 1802 Fg−1. The analysis revealed that the electrochemical properties of these electrodes were exceptional, which might have been impacted by the addition of ZIF-8. It is discovered that after 10,000 complete cycles, the CMZ electrode retains 77.52 % of its initial specific capacitance value, demonstrating exceptional cyclic stability at a 0.5 Ag−1 current density.