Toward a Mechanistic Model of Solid–Electrolyte Interphase Formation and Evolution in Lithium-Ion Batteries

: The formation of passivation fi lms by interfacial reactions, though critical for applications ranging from advanced alloys to electrochemical energy storage, is often poorly understood. In this work, we explore the formation of an exemplar passivation fi lm, the solid − electrolyte interphase (SEI), which is responsible for stabilizing lithium-ion batteries. Using stochastic simulations based on quantum chemical calculations and data-driven chemical reaction networks, we directly model competition between SEI products at a mechanistic level for the fi rst time. Our results recover the Peled-like separation of the SEI into inorganic and organic domains resulting from rich reactive competition without fi tting parameters to experimental inputs. By conducting accelerated simulations at elevated temperature, we track SEI evolution, con fi rming the postulated reduction of lithium ethylene monocarbonate to dilithium ethylene monocarbonate and H 2 . These fi ndings furnish fundamental insights into the dynamics of SEI formation and illustrate a path forward toward a predictive understanding of electrochemical passivation.