Phenomenological modelling of cycling-induced damage in the metal-ion battery electrode

This work addresses a pivotal challenge in metal-ion batteries, namely the structural degradation and damage of electrodes, which profoundly impacts the operational performance and overall longevity of metal-ion batteries. A chemo-mechanical model is introduced, including the interaction between the degradation/damage induced by chemical reaction and the damage-dependent mechanical stress/strain during electrochemical cycling. A viscoplastic constitutive relationship is developed that explicitly considers the effects of both the mechanical and chemical damages. The contributions of the mechanical and chemical damages are incorporated in the model, employing scalar damage variables to depict the damage states. We numerically analyze the dynamic evolution of stress, plastic strain, and damages throughout multiple lithiation and de-lithiation cycles and illustrate the effects of electrochemical cycling on surface damage and stress distribution. The experimental results support the developed model, with the numerical results closely matching the experimental results for the retaining of the capacity of a graphite-based lithium-ion half-cell. The numerical results reveal the importance of the damage parameters in describing the evolution of the structural damage in electrodes during electrochemical cycling. This study enriches our understanding of the structural damage in electrodes during electrochemical cycling and has great potential to improve the design of metal-ion batteries.