Electric‐Dipole Coupling Ion‐Dipole Engineering Induced Rational Solvation‐Desolvation Behavior for Constructing Stable Solid‐State Lithium Metal Batteries

Solid‐state polymer electrolytes (SPEs) with high ionic conductivity, a wide voltage window, and an ultra‐stability electrolyte/electrode interface are essential for practical applications of solid lithium‐metal batteries but particularly challenging. The key to overcoming these long‐term obstacles lies in the rational design of the Li+ solvation‐desolvation behavior in SPEs. Herein, we propose an electric‐dipole coupling ion‐dipole strategy to modulate the Li+ solvation structure and enhance Li+ desolvation kinetics. The experimental characterizations and theoretical calculations indicate that the free solvents and FSI− are anchored by ion‐dipole interactions, which facilitate the transfer of Li+ and obtain a wide electrochemical stability window. Coupling the electric‐dipole interactions that promote lithium salt dissociation and rapid ion desolvation contributes to obtaining more mobile Li+ and realizing an inorganic‐rich electrolyte/electrode interface. Benefiting from the above benefits, the assembled lithium symmetric cells and the full cells demonstrate ultra‐long cycling life. More importantly, full cells with high‐loading cathodes (LiFePO4 with 11.25 mg cm−2, NCM811 with 7.84 mg cm−2) and pouch cell still display stable cycling.This research gives valuable insights into regulating the solvation‐desolvation behavior in SPEs and facilitates the development of state‐of‐the‐art Li metal batteries.