Modeling damage to the solid electrolyte matrix in composite electrodes: role of ionic conductivity

Solid composite electrodes play a critical role in all-solid-sate-batteries, but intercalation-induced expansion of the active materials will cause damage in the matrix and affect the performance of battery. In this work, damage evolution in the solid electrolyte (SE) matrix related to migration of ions/electrons in SE matrix, transport of species in electrode particles, local current densities at the SE/active materials interface, and mechanical deformation of the structure is investigated based on the non-local damage approach. The influence of mechanical damage on the electrochemical performance is modeled by coupling the damage variable and ionic conductivity of the SE. The results indicate that for low ionic conductivity, the damage of the SE matrix is inhomogeneous across the composite electrodes, while for high ionic conductivity, the damage of the SE matrix is uniform. We also investigate the effect of damage on the electrochemical performance of battery and it is shown that capacity loss is significant for low ionic conductivity, but shows little variation under high ionic conductivity.