Ether‐based electrolytes show great potential in low‐temperature lithium metal batteries (LMBs) for their low viscosity and decent reduction stability. However, conventional ethers with multidentate chelate sites suffer from low oxidation stability and high desolvation energy barrier due to the strong coordination between oxygen and Li+. Herein, cyclic tetrahydropyran (THP) with a unidentate site is designed as a solvent, and fluoroethylene carbonate (FEC) and lithium nitrate (LiNO3) serve as additives for low‐temperature LMBs. The cyclic strain and unidentate chelate effect endow THP with a weak affinity to Li+ ions, which accelerates Li+ desolvation process and induces the anion‐derived electrode/electrolyte interface at low temperature. The formed inorganic‐rich interface further improves the oxidation stability and expedites the interfacial ion transportation. As a result, the assembled Li‐LiNi0.8Mn0.1Co0.1O2 (NMC811) cell stably cycles with 87% capacity retention after 100 cycles at −40 °C and 4.5 V. The 2.7 Ah Li‐NMC811 pouch cell with an energy density of 403 Wh kg−1 delivers 53% of the room‐temperature capacity at −50 °C. This work reveals that regulating the chelate site of solvents can well optimize the electrolytes to realize low‐temperature LMBs.

中文翻译：

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一种用于低温高压锂金属电池的四氢吡喃基弱溶剂化电解质


醚基电解质因其低粘度和良好的还原稳定性而在低温锂金属电池 （LMB） 中显示出巨大的潜力。然而，由于氧和 Li+ 之间的强配位，具有多齿螯合位点的常规醚具有低氧化稳定性和高脱溶剂分能垒。在本文中，具有单相位点的环状四氢吡喃 （THP） 被设计为溶剂，氟碳酸乙烯酯 （FEC） 和硝酸锂 （LiNO3） 用作低温 LMB 的添加剂。环状应变和单齿螯合物效应赋予 THP 对 Li+ 离子的弱亲和力，从而加速 Li+ 脱溶剂化过程并在低温下诱导阴离子衍生的电极/电解质界面。形成的富含无机物的界面进一步提高了氧化稳定性并加快了界面离子传输。因此，组装好的 Li-LiNi0.8Mn0.1Co0.1O2 （NMC811） 电池在 -40 °C 和 4.5 V 下循环 100 次后，以 87% 的容量保持率稳定循环。能量密度为 403 Wh kg-1 的 2.7 Ah Li-NMC811 软包电池在 -50 °C 时提供 53% 的室温容量。 这项工作揭示了调节溶剂的螯合位点可以很好地优化电解质以实现低温 LMBs。