Solvation Dynamics of Lithium-Sulfur Electrochemical Reaction Systems

Li-S dissolution during charge-discharge process presents a fundamental dilemma in the design and fabrication of Li-S batteries. Hence, new paradigms of solid-state Li-S electrochemical reaction mechanism enabled by sub-nano confinement of sulfur are being explored. A great advantage of this mechanism is its compatibility with different types of electrolytes. However, the solvation energy and structure also play important roles in this mechanism. In this poster, we investigate the solvation effects of the Lithium bis(trifluoromethanesulfonyl)imide(Li[TFSI]) electrolyte based on various ether solvents, such as mono-(G1), di-(G2), tri-(G3), tetra-glyme(G4), 15-Crown-5(G5), using classical and ab initio MD simulations. Specifically, we analyze in detail the solvation shell around the Li-ion as well as the binding energy per Li-ion. Our results show that depending on the type of solvent considered, different number of molecules are required to form a stable solvent shell around the Li-ion. In addition, we note that the G5 solvent forms the most stable solvation shell amongst all the solvents. Our simulation model gives the results which are in excellent agreement with experimental observations.