A variety of electrolyte engineering strategies have been introduced to extend the cycle life of lithium metal batteries (LMBs). These strategies can be largely grouped into two categories: those that induce a solvent-driven vs those that induce an anion-driven solid electrolyte interphase (SEI) layer. Although each strategy has proven to be effective for SEI manipulation, they are not yet comprehensively understood. Here, lithium salts with different dissociation abilities are systematically screened. Among those screened, highly dissociative lithium bis(trifluoromethane) sulfonimide (LiTFSI) with a high lowest unoccupied molecular orbital (LUMO) level is found to have enhanced cyclability by promoting the reduction of the solvent, fluoroethylene carbonate (FEC). Moreover, 1,2-dimethoxyethane (DME) as a cosolvent induces free FEC from the solvation sheath to further improve the cycle life by forming an SEI layer with uniformly distributed fluorine-containing components. This study unveils the usefulness of free solvent molecules by manipulating the solvation environments in achieving high-performance LMBs.

中文翻译：

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锂金属电池中稳定界面的策略：游离溶剂衍生与阴离子衍生

已经引入了多种电解质工程策略来延长锂金属电池（LMB）的循环寿命。这些策略可以大致分为两类：诱导溶剂驱动的策略和诱导阴离子驱动的固体电解质界面 (SEI) 层的策略。尽管每种策略都已被证明对 SEI 操作有效，但它们尚未得到全面了解。在这里，系统地筛选了具有不同解离能力的锂盐。在筛选的那些中，发现具有高最低未占分子轨道 (LUMO) 能级的高度离解锂双（三氟甲烷）磺酰亚胺 (LiTFSI) 通过促进溶剂氟代碳酸亚乙酯 (FEC) 的还原来增强循环能力。此外，1，2-二甲氧基乙烷 (DME) 作为共溶剂从溶剂化鞘中诱导游离 FEC，通过形成含氟组分均匀分布的 SEI 层进一步提高循环寿命。这项研究通过控制溶剂化环境来揭示自由溶剂分子在实现高性能 LMB 方面的用途。