Modeling coupled electro-chemo-mechanical phenomena within all-solid-state battery composite cathodes

All-solid-state batteries (ASSBs) are promising candidates for next-generation energy storage. However, realizing their potential requires an understanding of their underlying coupled, multiphysics behaviors. In an effort to understand these complex interactions, the present paper develops and applies a finite-element phase-field model that represents coupled electro-chemo-mechanical behaviors in composite ASSBs cathodes. The model predicts stress distributions as well as fracture and phase separations under several operating conditions. The results show that structural disintegration and the resulting loss of active surface area creates tortuous pathways for Li and Li-ion transport, contributing to capacity fade. The model is used to investigate the sensitivity of cell performance to different variables. The model evaluates the effects of electrode/electrolyte material properties, such as material stiffness and fracture toughness; microstructural characteristics, such as porosity and void distribution; and operating conditions such as charge/discharge rates and externally applied pressure. The voltage responses are validated using previously published experimental measurements. The model can be used to inform microstructural design and operating conditions that minimize or prevent mechanical damage during multiphysical interactions in ASSBs.