Role of Solvent Isomerism in Mixed Carbonate Electrolytes for Li-Ion Batteries

Bonhyeop Koo, Hyejin Lee, Sunwook Hwang, Jaeho Lee, Young Kyu Han, Kyoung Ho Ahn, Chulhaeng Lee, Hochun Lee

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Current Li-ion battery (LIB) electrolytes employ mixed solvents consisting of ethylene carbonate (EC) and linear carbonates (LCs). Notably, the ion conductivities of the EC/LC electrolytes follow the order dimethyl carbonate > ethyl methyl carbonate > diethyl carbonate despite the similar physicochemical properties of the three LCs. However, the origin of this order remains elusive. In this study, we elucidated the important role of conformational isomerism of the LC solvent on salt dissociation in 0.1-3.0 M LiPF6 EC/LC solutions, using Raman spectroscopy and dielectric relaxation spectroscopies, along with first-principles calculations. The conductivity trend is closely related to the difference in the degree of salt dissociation, which, in turn, is determined by the fraction of the polar cis-trans-LC conformer, as this conformer participates in Li-ion solvation as readily as EC does. This study demonstrates the critical role of the conformational isomerism of the solvents in the electrolyte conductivity, indicating the feasibility of utilizing solvent isomerism to tune the bulk transport properties of electrolytes.

Original languageEnglish
Pages (from-to)18271-18278
Number of pages8
JournalJournal of Physical Chemistry C
Volume127
Issue number37
DOIs
StatePublished - 21 Sep 2023

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