January 30, 2025
Journal Article
A Systematic Study on the Effects of Solvating Solvents and Additives in Localized High-Concentration Electrolytes over Electrochemical Performance of Lithium-Ion Batteries
Abstract
In this work, localized high-concentration electrolytes (LHCEs) based on five different solvents: 1,2-dimethoxyethane, dimethyl carbonate, trimethyl phosphate, tetramethylene sulfone and acetonitrile, were systematically studied and compared in lithium-ion batteries (LIBs). It is revealed that in all these LHCEs, the unique solvation structure of LHCEs promotes the participation of lithium salt in the solid electrolyte interphase (SEI) formation, which enables solvents that were previously considered incompatible with graphite (Gr) electrode to achieve reversible lithiation/delithiation with Gr electrode. However, the long-term cycling performance of LIBs is still subject to the intrinsic properties of the solvent species in LHCEs. Such issue can be readily resolved by introducing a small amount of electrolyte additive into LHCEs. The synergetic decompositions among lithium salt, solvating solvent and additive yield highly effective SEIs and cathode electrolyte interphases (CEIs) in most of the studied LHCEs. This study reveals that both the structure and the composition of solvation sheaths in LHCEs have significant influence over SEI and CEI formation and consequently cycle life of LIBs, and LHCEs can be readily tuned to achieve superior cycling performance of energetically dense LIBs.Published: January 30, 2025