The Interaction of Ether-Based Functionalized Ionic Liquids in Lithium-Sulfur Batteries: A First-Principles Study.

Ionic liquids (ILs) as electrolytes in lithium-sulfur (Li-S) batteries effectively mitigate the shuttle effect. Solvated cationic ether-based ILs, comprising [Li(G1)], [Li(G2)], [LiG3], [LiG4], or [LiG6] paired with bis(trifluoromethyllsulfonyl)imide ([TFSA]) anions, are evaluated for their ability to suppress short-chain lithium polysulfide (LiPS: LiS, LiS, LiS) adsorption on lithium metal. The chelating capacity of solvated cations governs interactions with LiPSs and anions. Solvation via Li chelation prevents free Li fusion with LiPSs, reducing shuttle effects. Remarkably, the cyclic [LiG6] cation exhibits superior Li chelation, stability, and minimized LiPS adsorption compared to linear cations. Ab initio molecular dynamics simulations confirm ether-based ILs stabilize anions and lower LiPS-lithium surface reactivity. These findings highlight solvated cation ILs as tailored electrolytes to control interfacial LiPS behavior, advancing high-performance LiS battery design.