Electrochemical-mechanical coupled phase-field modeling for lithium dendrite growth in all-solid-state lithium metal batteries

All-solid-state lithium metal batteries represent leading candidates for the next generation of high-energy-density rechargeable batteries. However, the coupled mechanisms governing dendrite growth and crack propagation within solid-state electrolytes (SSEs) remain inadequately understood. To address this knowledge gap, we propose an electrochemical-mechanical coupled phase-field model designed to simulate the complex processes of lithium deposition and crack propagation in SSEs. This framework systematically examines the influence of initial defect characteristics—including morphology, dimensions, and fracture toughness—on dendrite penetration dynamics. Furthermore, it identifies potential initiation pathways for detrimental lithium deposition within the electrolyte bulk. The model also quantifies the critical role of electrolyte elastic modulus and grain boundary orientation in modulating deposition behavior. Notably, simulation results demonstrate concordance with existing experimental observations, thereby establishing a fundamental theoretical framework for understanding failure mechanisms. This work provides crucial mechanistic insights and predictive capabilities to guide the rational design of failure-resistant SSEs for all-solid-state lithium metal batteries.