Evolutionary Design for Anion-Derived Interphase Stability
Year: 2026
Type: preprint
Abstract: High-concentration electrolytes (HCEs) improve lithium-ion battery cycling by shifting interphase formation from the solvent to the anion, producing a more stable inorganic-rich interphase at the anode. However, the anions for HCEs has been mainly studied on FSI− and TFSI−, and the anion itself has received little systematic exploration relative to the solvent and the salt concentration. Here, anion chemical space is searched using evolutionary framework that couples genetic algorithm with quantum-chemical descriptors of reducibility, solvent coordination, and charge delocalization. Substructure analysis of the evolved populations identifies a sulfinimide (N−=S) core as the recurring motif in place of the sulfonyl chemistry of the reference anions, and a combinatorial scaffold-branch library built from these motifs exhibits distinction between the electronic and intermolecular contributions to anion performance. Charge localization is governed by the scaffold while solvent binding is set neither by scaffold nor by branch alone but by their specific pairing and by whether the two arms are chemically distinct. Higher-level solvation show that the leading candidates from the selected anion set exceed both baseline anions in bulk solvation, and transport calculations exhibit that every candidate carries a smaller Li+ first shell and diffuses faster than both baselines at concentrated salt content. Replacing a single sulfonyl oxygen with an imide nitrogen reorganizes the anion around a delocalized, asymmetrically substituted core and opens a salt chemistry for HCEs distinct from the sulfonyl imides in use today.
Source: ChemRxiv
Authors: Esra Ulgey Akgun, Brett M. Savoie
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7215130818