Electrodeposition mode effects on the electrochemical performance of MnO₂–NiO eco-friendly material for supercapacitor electrode application

In this study, we have used various electrodeposition techniques, namely direct and pulse chronoamperometry, to prepare MnO₂–NiO composite films from an acetate solution onto fluorine-doped tin oxide glass substrates (FTO). Subsequently, the metal oxide conversion process was carried out through a heat treatment at 300 °C for 5 h. We used X-ray Diffraction, Field-Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-ray Spectroscopy (EDX), and Fourier-Transform Infrared Spectroscopy (FTIR) to investigate the crystalline properties, compositions, and morphologies of the electrodeposited films. To evaluate the electrochemical performance, we conducted cyclic voltammetry (CV), galvanostatic charge–discharge tests (GCD), and electrochemical impedance spectroscopy (EIS). Specifically, when applying the pulse deposition mode (denoted as P), the FTO/MnO₂–NiO (P) film exhibited a specific capacitance of 375 Fg⁻¹ at a current density of 0.5 Ag⁻¹, meeting the required standard. This result confirms that the FTO/MnO₂–NiO (P) film is a promising alternative for electrode applications. Additionally, the film demonstrated an impressive 56.87% capacity retention after 1000 galvanostatic charge–discharge cycles at a current density of 2 Ag⁻¹.