Uncovering the Effect of Solid Electrolyte Interphase on Ion Desolvation for Rational Interface Design in Li‐Ion Batteries

Abstract The conventional knowledge of solid electrolyte interphases (SEIs) is limited to their ionic conductive and electron‐insulating properties. The solvation structure regulation in the new‐concept electrolytes always leads to the regulated SEI, resulting in the improvement of ion desolvation kinetics. However, the linkage between the improved kinetics and the regulated SEl remains unconnected at the atomic level. Herein, this work proposes that the SEI can function more by facilitating ion desolvation. Using quantum chemistry calculations, this work explores the ion desolvation processes with and without SEI. It is found the accelerated ion desolvation in the new‐concept electrolytes is directly attributed to the SEI rather than the regulated solvation structure. Based on the recognition of SEI's role, this work proposes an SEI‐aided ion desolvation model. This study bridges the SEI and battery kinetics at the atomic scale and redefines the functions of SEI, which are expected to steer the electrolyte design in batteries.