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)₂]⁺, [Li(G2)₂]⁺, [LiG3]⁺, [LiG4]⁺, or [LiG6]⁺ paired with bis(trifluoromethyllsulfonyl)imide ([TFSA]^-) anions, are evaluated for their ability to suppress short-chain lithium polysulfide (LiPS: Li₂S₁, Li₂S₂, Li₂S₄) 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.