Research progress on solid electrolyte interphase of lithium metal

Solid electrolyte interphase (SEI) is a passivation film formed on the surface of the lithium metal anode when the lithium metal battery is first charged and discharged. This interphase has a crucial impact on the cycle performance and safety of lithium metal batteries. A good understanding of SEI will help researchers develop lithium metal batteries with longer cycle life and higher safety. This paper reviews the research progress on solid electrolyte interphase in lithium metal batteries. It introduces the composition and structure of SEI, organizes the formation conditions and roles of various common components. Two main models used to describe the structure of SEI, namely the mosaic model and the laminar model, are demonstrated. Additionally, it summarizes key factors that affect the composition and structure of SEI such as electrolyte additives, electrode potentials, temperature, and current density etc. We also introduced the latest research progress in achieving interface stability control by introducing electrolyte additives and constructing artificial SEI membranes, and finally looked forward to the future research directions of SEI membranes. © 2023 Materials China. All rights reserved.