Coordination and ionic solvation

Abstract: : Over the past two decades, the solid − electrolyte interphase (SEI) layer that forms on an electrode ’ s surface has been believed to be pivotal for stabilizing the electrode ’ s performance in lithium-ion batteries (LIBs). However, more and more researchers currently are realizing that the metal-ion solvation structure (e.g., Li + ) in electrolytes and the derived interfacial model (i.e., the desolvation process) can a ff ect the electrode ’ s performance signi fi cantly. Thus, herein we summarize recent research focused on how to discover the importance of an electrolyte ’ s solvation structure, develop a quantitative model to describe the solvation structure, construct an interfacial model to understand the electrode ’ s performance, and apply these theories to the design of electrolytes. We provide a timely review on the scienti fi c relationship between the molecular interactions of metal ions, anions, and solvents in the interfacial model and the electrode ’ s performance, of which the viewpoint di ff ers from the SEI interpretations before. These discoveries may herald a new, post-SEI era due to their signi fi cance for guiding the design of LIBs and their performance improvement, as well as developing other metal-ion batteries and beyond.