Modeling Supercapacitors with the Simplified Randles Circuit: Analyzing Electrochemical Behavior through Cyclic Voltammetry and Galvanostatic Charge-Discharge

Cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) are crucial analytical techniques for investigating energy storage devices like supercapacitors. This study employed a simplified Randles circuit model to simulate the CV and GCD characteristics of a supercapacitor. The results revealed distinct differences between the CV and GCD curves generated by the simplified Randles model and the commonly reported RC circuit models. Specifically, the RC circuit model shows current saturation at high voltages, which does not match the observed linear-like upper region behavior in supercapacitor CV curves, while the simplified Randles circuit model can capture this behavior. Notably, the simplified Randles model exhibited a low root-mean-square error (RMSE) in fitting experimental data, indicating its reliability in representing the real supercapacitor system. This discovery highlights the potential of the simplified Randles model for studying and optimizing energy storage devices, further emphasizing the significance of CV and GCD measurements in electrochemistry.