Dual-Anion Regulated SEI Formation Enabling Stable and Thin Interphases for Lithium-Metal Anodes
발표자
이제민 (경북대학교)
연구책임자
유지영 (경북대학교)
초록
내용
A dual-anion locally concentrated ionic liquid electrolyte (D-LCILE), using LiFSI and LiTFSI salts, forms a thin, uniform, and LiF-rich solid electrolyte interphase (SEI) for stable lithium-metal batteries. Raman spectroscopy and molecular dynamics simulations show that dual-anion chemistry promotes aggregate (AGG)-rich Li⁺ solvation, enhancing anion co-migration during charging. This allows FSI⁻ to reach the anode and decompose into LiF, a chemically and mechanically stable SEI component. AIMD simulations reveal fast F dissociation from FSI⁻, while TFSI⁻ supports Li⁺ transport and wettability via weak coordination. ToF-SIMS and XPS depth profiling verify high fluorine content in the SEI interior. SEM shows denser, thinner Li deposits with D-LCILE. Full-cell tests exhibit 99.93% capacity retention over 200 cycles. This dual-anion strategy offers a unified route to optimize solvation structure, SEI composition, and interfacial stability in high-energy lithium-metal batteries.