To this end, a pressure-electrochemical coupling model based on COMSOL Multiphysics was developed, incorporating semi-empirical dynamic parameters to mirror actual operating conditions. The deterioration of the cathode–electrolyte interphase (CEI) formed at the solid electrolyte and anode interface was a particular focus, and a model was developed that reflects chemical and mechanical changes such as increased CEI thickness, decreased ion conductivity, and increased interfacial resistance.
The simulation results demonstrated the efficacy of integrating these two models in predicting the impact of external pressure on CEI growth and interfacial resistance formation. It was observed that, under suitable pressure conditions, interfacial adhesion was enhanced and CEI growth was suppressed, thereby leading to enhanced electrochemical performance. Furthermore, the augmentation of the volume fraction of the active material and solid electrolyte led to the stabilization of the ion conduction path. The optimal pressure range was determined with consideration of the potential for mechanical damage due to excessive pressure and aberrant CEI growth.
This study presents a foundational technology that can contribute to the design of high-performance, long-life all-solid-state batteries and process optimization through a simulation-based model that reflects the effect of external pressure on CEI degradation.