Void Formation and Evolution Dynamics for Lithium Metal and Solid Electrolyte Interfaces

Solid-state batteries (SSBs) with lithium (Li) metal anodes have emerged as promising candidates for next-generation energy storage systems, offering higher energy density and improved safety than conventional Li-ion batteries. However, their practical implementation is hindered by critical challenges, particularly void formation at the Li-solid electrolyte (SE) interface, which affects transport pathways and accelerates interfacial degradation. In this work, we investigate how the mechanistic interplay between electro-dissolution kinetics and vacancy diffusion at the Li-SE interface dictates the evolution of solid-solid contact and void morphology during stripping. We examine the underpinning role of temperature in improving Li diffusion kinetics and enhancing the regime of stable contact under different stripping conditions. Additionally, we evaluate the impact of surface heterogeneities (e.g., grain boundaries in Li metal), which induce spatial variations in local reaction and transport rates, leading to the rapid formation of surface pits. We identify distinct interface stability regimes, revealing how nonuniform stripping dynamics govern morphological evolution and electrochemical contact at the Li metal interface. Overall, this study provides critical mechanistic insights into the coupled influence of interfacial kinetics, operating conditions, and surface heterogeneities on void evolution, guiding design strategies for stable solid-solid interfaces in SSBs.