Mechanistic prediction of long-term degradation in Li-metal anodes via connectivity-aware multiphase phase-field modeling

초록

Lithium (Li)-metal anodes offer exceptional theoretical capacity, yet their long-term performance is fundamentally limited by dendrite-induced degradation and the accumulation of electrochemically isolated dead Li. Predicting how these degradation processes evolve over many charge-discharge cycles remains challenging due to the lack of models that can explicitly distinguish active Li from dead Li. Here, we develop a multi-phase electrochemical phase-field framework that tracks the coupled evolution of ion transport, interfacial reactions, dendrite growth, and dead Li formation. The model incorporates a connectivity-based criterion to identify dead Li and enables quantitative evaluation of degradation under varying electrochemical and material parameters. Simulations show that higher cycling rates accelerate dead Li accumulation and increase transport resistance, while improved SEI stability suppresses branching and reduces degradation. In contrast, strong anisotropy in Limetal surface energy promotes rapid tip-oriented dendrite growth and increases the likelihood of fragment detachment. These results provide a mechanistic understanding of how operating conditions, SEI stability, and crystallographic anisotropy influence long-term anode degradation, offering guidance for improving the stability of Li-metal batteries.

키워드