Realigning the Chemistry and Parameterization of Lithium‐Sulfur Battery Models to Accommodate Emerging Experimental Evidence and Cell Configurations

Abstract

Experimental insights into lithium-sulfur (LiS) battery chemistry have resulted in practical improvements in cell coulombic efficiency, sulfur utilization, and cycle life. However, optimization of this complex battery chemistry requires experimentally aligned modeling tools. A porous electrode theory-based model incorporating key electrolyte dissociation chemistry is developed for the LiS cell. The proposed chemistry produces a radical anion species that is widely observed spectroscopically in LiS electrolytes. We explore the implications of radical anion formation on the current-voltage behavior within the context of a state-of-art high energy density LiS cell with low electrolyte: sulfur (E/S) ratio and ideally-protected anode. Parameters describing the dissociation reaction equilibrium and kinetics are shown to alter the electrolyte speciation in ways that can be linked to observations from LiS electrolyte engineering experiments.