Lithium-Lithium Correlations and the Emergence of Transport Properties in Solvate Ionic Liquid Electrolytes
Year: 2026
Type: preprint
Abstract: Solvate ionic liquids (SILs), equimolar mixtures of lithium salts and chelating glymes, are promising electrolytes for energy storage due to their high thermal stability and low vapor pressure. However, the low lithium transference numbers and modest ionic conductivities of SILs limit device performance. Here, long-timescale molecular dynamics simulations combined with transport characterization identify the Li+-Li+ structural decorrelation as the key descriptor governing ion transport in SILs composed of lithium bis(trifluoromethanesulfonyl)imide and glymes of various lengths. These SILs have extended ionic networks in which anions bridge multiple Li+ centers, generating long-lived structural correlations. SIL ion transport is initiated by speciation exchange, which disrupts the ionic network and leads to structural decorrelation on nanosecond timescales. Decreasing glyme chain length increases anion bridging, slows structural decorrelation, and decreases ionic conductivity, while increasing lithium transference. These results establish structural decorrelation as a key descriptor of transport in SILs. While the anion-mediated decorrelation is demonstrated for SILs, this framework is general and can be applied to any high concentration electrolyte in which transport emerges from the reorganization of correlated ionic networks.
Source: ChemRxiv
Institution: Louisiana State University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214628201