Developing an innovative theoretical model for analyzing cyclic voltammetry in hybrid supercapacitors

Cyclic voltammetry (CV) is a vital analytical technique used to investigate various energy storage devices, including hybrid supercapacitors. The incorporation of suitable modeling techniques can significantly enhance our understanding of the electrochemical behavior exhibited by these devices. This study presents a novel theoretical model designed to simulate the CV of hybrid supercapacitor electrodes and full-cell hybrid supercapacitors. The results demonstrate that the proposed model effectively captures the combination of electric double-layer capacitance (EDLC) and pseudocapacitance mechanisms within a single CV curve, exhibiting a saturated current characteristic of EDLC and a peak associated with it. Variations in model parameters significantly alter the CV shape, aligning with physical interpretations. In addition to visualizing the model with various parameters, we introduces the non-ideal behavior in the hybrid supercapacitor by defining the dynamic weight ratio caused by the proposed leakage phenomena on the EDLC surface. Notably, the model for a single electrode shows excellent agreement with experimental CV data from NaCoO₂/GF and NaCoO₂ electrodes in a three-electrode system. Additionally, a full-cell CV model, based on charge balance principles, successfully introduces a new E-Q curve. This model also aligns well with experimental data for the NaCoO₂/GF//AC hybrid supercapacitor system, underscoring the potential of this theoretical framework for studying and optimizing hybrid supercapacitor energy storage devices.