(348d) Characterization of Reaction Mechanisms on Lithium Metal Anodes of Lithium-Sulfur Batteries

Authors: 
Camacho-Forero, L. E., Texas A&M University
Balbuena, P. B., Texas A&M University

The Lithium-Sulfur (Li-S) battery is a promising and suitable candidate among rechargeable battery systems beyond the conventional Lithium-ion (Li-ion) battery, due to its low cost, significantly higher energy density than the Li-ion cell and high theoretical capacity. However, there are some drawbacks related to cycle life and safety requirements that do not make Li-S batteries suitable for commercialization yet. Besides, some of the main issues are associated with the lithium anode where electrolyte decomposition and Li-dendrite formation on the surface take place in presence of the soluble polysulfide species that migrate to the anode due to the ”shuttle” effect. Therefore, a rigorous understanding of the reaction mechanisms of the different set of reactions that can take place on the Li-anode will help us to elucidate the low performance of such system and hence, guide improvements in materials in order to extended battery life. In this work, we use first principles computational techniques such as density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations in order to study the reaction mechanisms of several electrolyte solutions on the Li-anode including: pure solvents such as 1, 2-dimethoxyethane (DME), 1, 3-dioxolane (DOL) and ethylene carbonate (EC), and solution in 1M solution of Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). In addition, the effect of soluble polysulfides species such as S8Li2, S6Li2 and S4Li2 at the anode as well as their decomposition are also investigated.