Correlating Solid Electrolyte Interphase Composition with Dendrite‐Free and Long Life‐Span Lithium Metal Batteries via Advanced Characterizations and Simulations

Abstract Lithium metal anode attracts great attention because of its high specific capacity and low redox potential. However, the uncontrolled dendrite growth and its infinite volume expansion during cycling are extremely detrimental to the practical application. The formation of a solid electrolyte interphase (SEI) plays a decisive role in the behavior of lithium deposition/dissolution during electrochemical processing. Clarifying the essential relationship between SEI and battery performance is a priority. Research in SEI is accelerated in recent years by the use of advanced simulation tools and characterization techniques. The chemical composition and micromorphology of SEIs with various electrolytes are analyzed to clarify the effects of SEI on the Coulombic efficiency and cycle life. In this review, the recent research progress focused on the composition and structure of SEI is summarized, and various advanced characterization techniques applied to the investigation of SEI are discussed. The comparisons of the representative experimental results and theoretical models of SEI in lithium metal batteries (LMBs) are exhibited, and the underneath mechanisms of interaction between SEI and the electrochemical properties of the cell are highlighted. This work offers new insights into the development of safe LMBs with higher energy density.