Modeling first stages of solid-electrolyte interphase (SEI) in LiPF₆/EC electrolytes using molecular dynamics simulations

The performance of lithium-ion batteries (LiB) using organic electrolytes depends strongly in the formation of a stable solid electrolyte interphase (SEI) film. Elucidating the dynamic evolution and spatial composition of the SEI is a very important step towards understanding the stability of the structures and its growth during the formation cycles of LiB. We propose a classical molecular dynamics simulation protocol for predicting the first stages of the SEI using an accelerated reaction method involving the decomposition of EC and LiPF₆ molecules in the electrolyte. We are able to simulate, for tens of nanoseconds, the accelerated formation of SEI components near the anode surface, including the production of gases (C₂H₄), inorganic (Li₂CO₃, and LiF) and organic (LEDC) species. We expect to expand this protocol to different electrolyte compositions and additives.