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

Authors: Junhao Wang, Jing Luo, Haichuan Wu, Xiaoyu Yu, Xiaohong Wu, Zhengang Li, Haiyan Luo, Haitang Zhang, Yuhao Hong, Yeguo Zou, Shuohui Cao, Yu Qiao*, Shi-Gang Sun

Abstract: 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.

Full-Link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202400254