Enhanced electrochemical performance of NiO surfaces via selective Li + doping

The effects of selective Li doping on NiO films' structural, optical and electrochemical properties were investigated in this study. Our results highlighted a strong correlation among bandgap modulation, conductivity and selective Li-ion doping on the surfaces of NiO films. Electrochemical impedance spectroscopy (EIS) demonstrated the impact of subtle Li doping on the electrochemical behavior of the NiO thin films due to an increase in the diffusion resistance ( ) up to 49.32 Ω for 0.5% Li-doped NiO, suggesting faster and more efficient hole transport from the electrode to electrolyte unlike NiO:Li4.0% electrodes. A linear and symmetric forward curve demonstrating ohmic behaviour was observed only for 0.5% Li-doped NiO thin films during current-voltage ( - ) analysis. Interestingly, the 0.5% Li-doped NiO films, which exhibited the largest anodic peak area in the CV curve under illumination, outperformed the 4.0% Li-doped NiO films in electrochemical activity, emphasizing the effectiveness of minimal doping.