Electrochemical modeling of hybrid electrode systems under galvanostatic charge–discharge: an experimentally fitted approach

Growing interest in sustainable energy technologies has led to the development of hybrid energy storage systems, which aim to merge the advantages of batteries and supercapacitors by achieving both high energy and power densities. Despite their promise, a clear understanding of the electrochemical behavior in hybrid electrodes remains limited. This work proposes a new theoretical approach that captures both capacitive and diffusive behaviors through an electrical circuit representation governed by dynamic capacitance. The model successfully replicates a wide range of GCD profiles by adjusting key parameters. It also allows estimation of the relative contributions of energy storage mechanisms, a capability rarely achieved beyond Dunn's method. Its reliability is evidenced by strong agreement with experimental data, yielding a high R²value. Additionally, when unified with the concept of charge balance, the model reconstructs the full-cell GCD profile of hybrid supercapacitors in a manner consistent with experimental observations. These outcomes suggest that the model offers a valuable tool for understanding and optimizing next-generation hybrid storage devices.