The electrochemical performances of lithium metal batteries are determined by the kinetics of interfacial de-solvation and ion transport, especially at low-temperature environments. Here, a novel electrolyte that easily de-solvated and conducive to interfacial film formation is designed for low-temperature lithium metal batteries. A fluorinated carboxylic ester, diethyl fluoromalonate (DEFM), and a fluorinated carbonate, fluoroethylene carbonate (FEC) are used as solvents, while high concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is served as the solute. Through tailoring the electrolyte formulation, the lithium ions in the high concentrated fluorinated carboxylic ester electrolyte are mainly combined with anions, which weakens the bonding strength of lithium ions and solvent molecules in the solvation structure, beneficial to the de-solvation process at low temperature. The fluorinated carboxylic ester (FCE) electrolyte enables the LiFePO₄ (LFP) | Li half-cell achieves a high capacity of 91.9 mAh g⁻¹ at −30 °C, with high F content in the interface. With optimized de-solvation kinetics, the LFP | Li full cell remains over 100 mAh g⁻¹ at 0 °C after cycling 100 cycles. Building new solvents with outstanding low-temperature properties and weaker solvation to match with Li metal anode, this work brings new possibilities of realizing high energy density and low temperature energy storage batteries.

中文翻译：

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定制电解质溶剂化结构实现的高性能低温锂金属电池

锂金属电池的电化学性能取决于界面去溶剂化和离子传输的动力学，尤其是在低温环境下。在这里，一种易于去溶剂化并有利于界面膜形成的新型电解质被设计用于低温锂金属电池。氟化羧酸酯氟丙二酸二乙酯 (DEFM) 和氟化碳酸酯氟代碳酸亚乙酯 (FEC) 用作溶剂，而高浓度双（三氟甲磺酰基）亚胺锂 (LiTFSI) 用作溶质。通过调整电解液配方，高浓度含氟羧酸酯电解液中的锂离子主要与阴离子结合，削弱了溶剂化结构中锂离子与溶剂分子的结合强度，有利于低温脱溶剂化过程。氟化羧酸酯 (FCE) 电解质使 LiFePO₄ (LFP) | ^{锂半电池在-30 °C 时实现了 91.9 mAh g -1}的高容量，界面中具有高 F 含量。通过优化的去溶剂化动力学，LFP | 在循环 100 次循环后，锂全电池在 0 °C 时保持超过 100 mAh g ^{-1 。}构建具有优异低温性能和较弱溶剂化作用的新型溶剂以匹配锂金属负极，为实现高能量密度和低温储能电池带来了新的可能性。