Visualizing and Regulating Dynamic Evolution of Interfacial Electrolyte Configuration during De‐solvation Process on Lithium‐Metal Anode

Acting as a passive protective layer, solid‐electrolyte interphase (SEI) plays a crucial role in maintaining the stability of the Li‐metal anode. Derived from the reductive decomposition of electrolytes (e.g., anion and solvent), the SEI construction presents as an interfacial process accompanied by the dynamic de‐solvation process during Li‐metal plating. However, typical electrolyte engineering and related SEI modification strategies always ignore the dynamic evolution of electrolyte configuration at the Li/electrolyte interface, which essentially determines the SEI architecture. Herein, by employing advanced electrochemical in‐situ FT‐IR and MRI technologies, we directly visualize the dynamic variations of solvation environments involving Li+‐solvent/anion. Remarkably, a weakened Li+‐solvent interaction and anion‐lean interfacial electrolyte configuration have been synchronously revealed, which is difficult for the fabrication of anion‐derived SEI layer. Moreover, as a simple electrochemical regulation strategy, pulse protocol was introduced to effectively restore the interfacial anion concentration, resulting in an enhanced LiF‐rich SEI layer and improved Li‐metal plating/stripping reversibility.