Clarifying the structure–performance relationship for solvent fluorination in liquid electrolytes

Characterize the relationship between the position and degree of solvent fluorination and the resulting performance of lithium battery liquid electrolytes to enable structure-guided solvent design.

Background

The authors investigate model transferability to fluorinated derivatives of common carbonate and ester solvents and report that, despite qualitative trend capture, quantitative accuracy depends on training coverage of relevant functional groups. They note the widespread use of fluorination to improve electrochemical performance, SEI formation, and fire resistance, but also acknowledge that the precise mapping from fluorination site and degree to electrolyte performance remains unclear.

This explicit uncertainty highlights a fundamental open question crucial for rational solvent design and for improving MLFF generalizability to novel fluorinated chemistries.