The formation of passivation films 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 film, 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 first time. Our results recover the Peled-like separation of the SEI into inorganic and organic domains resulting from rich reactive competition without fitting parameters to experimental inputs. By conducting accelerated simulations at elevated temperature, we track SEI evolution, confirming the postulated reduction of lithium ethylene monocarbonate to dilithium ethylene monocarbonate and H2. These findings furnish fundamental insights into the dynamics of SEI formation and illustrate a path forward towards a predictive understanding of electrochemical passivation.
Supporting Information: Towards a Mechanistic Model of Solid-Electrolyte Interphase Formation and Evolution in Lithium-ion Batteries
Supporting information for "Towards a Mechanistic Model of Solid-Electrolyte Interphase Formation and Evolution in Lithium-ion Batteries". Contains: Computational methods; lists of molecules and reactions included in microkinetic simulations; example average trajectory; simulations with varying rates of lithium recoordination; discussion of SEI formation with different negative electrode chemistries; discussion of the possibility of oligomerization and polymerization of byproducts of SEI formation; discussion of the rate of EC ring-opening.