Modeling supercapacitors with the simplified Randles circuit: Analyzing electrochemical behavior through cyclic voltammetry and Galvanostatic charge-discharge

•The simplified Randles circuit model employed in this study successfully reproduces the linear-like characteristics of the cyclic voltammetry (CV) curve observed at high potentials, a defining feature of supercapacitor systems. This behavior is not captured by the conventional RC circuit model commonly used to explain supercapacitor behavior.•The simplified Randles circuit model utilized in this work also accurately replicates the non-linear behavior exhibited in the galvanostatic charge/discharge (GCD) data, which is a typical experimental observation for supercapacitors. This non-linear trend cannot be reproduced by the RC model, which predicts a linear GCD response.•The simplified Randles circuit model employed here is able to closely fit the experimental data for both GCD and CV, establishing it as a reliable model for supercapacitor systems. 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. [Display omitted]