文献类型：期刊文献

英文题名：Revealing Lithium Ion Transport Mechanisms and Solvation Structures in Carbonate Electrolytes

作者：Pan, Junkun[1];Charnay, Aaron P.[1];Zheng, Weizhong[2];Fayer, Michael D.[1]

机构：[1]Stanford Univ, Dept Chem, Stanford, CA 94305 USA;[2]East China Univ Sci & Technol, Sch Chem Engn, State Key Lab Chem Engn, Shanghai 200237, Peoples R China

年份：2024

卷号：146

期号：51

起止页码：35329

外文期刊名：JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

收录：;EI(收录号：20245017524564);WOS:【SCI-EXPANDED(收录号:WOS:001375072500001)】；

基金：This work was supported by the National Science Foundation, Division of Chemistry, award number 2319637. Part of this work was performed at the Stanford Nano Shared Facilities (SNSF), supported by the National Science Foundation under award ECCS-2026822.

语种：英文

外文关键词：Carbonation - Diffusion - Electrolytic cells - Spectroscopic analysis - Vortex flow

摘要：Optimizing lithium-ion battery (LIB) electrolytes is essential for high-current applications such as electric vehicles, yet experimental techniques to characterize the complex structural dynamics responsible for the lithium transport within these electrolytes are limited. In this study, we used ultrafast infrared spectroscopy to measure chemical exchange, spectral diffusion, and solvation structures across a wide range of lithium concentrations in propylene carbonate-based LiTFSI (lithium bis(trifluoromethanesulfonimide) electrolytes, with the CN stretch of phenyl selenocyanate as the long-lived vibrational probe. Phenyl selenocyanate is shown to be an excellent dynamical surrogate for propylene carbonate in Li+ solvation clusters. A strong correlation between exchange times and ionic conductivity was observed. This correlation and other observations suggest structural diffusion as the primary transport mechanism rather than vehicular diffusion. Additionally, spectral diffusion observables measured by the probe were directly linked to the desolvation dynamics of the Li+ clusters, as supported by density functional theory and molecular dynamics simulations. These findings provide detailed molecular-level insights into LIB electrolytes' transport dynamics and solvation structures, offering rational design pathways to advanced electrolytes for next-generation LIBs.