Approaching the Reactivity of Anions in Battery Electrolytes via Conceptual Density Functional Theory

Abstract

The practical deployment of batteries with superior energy and power densities is, among other factors, prohibited by the lack of suitable electrolyte formulations. While first-principles design promises accelerated discovery of practical battery electrolytes, its high computational cost limits the chemical space that can be analysed through screening. Herein, we show a computationally inexpensive approach, using descriptors within the framework of conceptual density functional theory, that can provide valuable insights into the reactivity of battery electrolyte components. By focusing on anions in liquid electrolytes for which abundant experimental data is available for benchmarking, we explore several descriptors against key experimental observables for a series of salts (LiPF6, LiBF4, LiTFSI, LiDFOB, LiTDI). We show that the descriptors evaluated for single species can provide insights consistent with those obtained from experiments or more complex models, while maintaining a favourable computational cost. This establishes conceptual density functional theory as a promising tool for high-throughput screening of electrolyte components (salts, solvents, diluents, additives).