Descriptors for Electrolyte-Renormalized Oxidative Stability of Solvents in Lithium-Ion Batteries.

Abstract

Electrolyte stability against oxidation is one of the important factors limiting the development of high energy density batteries. The highest occupied molecular orbital (HOMO) level of solvent molecules has been traditionally used for understanding trends in their oxidative stability, but this assumes a noninteracting environment. However, solvent HOMO levels are renormalized because of molecules in their solvation shells. In this work, we first demonstrate an inexpensive and accurate method to determine the HOMO level of the solvent followed by simple descriptors for renormalization of the HOMO level due to different electrolyte components. The descriptors are based on Gutmann donor and acceptor numbers of the solvent and other components. The method uses fast generalized gradient approximation-level density functional theory calculations compared to previously used expensive, experimental data-dependent methods. This method can be used to screen for unexplored stable solvents among the large number of known organic compounds to design novel high-voltage stable electrolytes.