As the holy grail anode, lithium (Li) metal has attracted considerable interest in developing next-generation high-energy–density batteries. However, Li dendrites due to the poorly protected solid electrolyte interphase (SEI) during the Li plating process largely limit the Li application. Here, we report an effective electrolyte additive, i.e., 2,2,2-Trifluoroethyl trifluoroacetate (2,2,2-TFTF) as highly efficient inhibitor against growth of Li dendrites by facile mediation of SEI layer. DFT calculations and a series of characterization results indicate that the additive greatly favors formation of more protective SEI layer on the Li anode and homogeneous Li deposition. Strikingly, with 4% additive, the Li|Li cell showed a long cycle life of 750 h and the Li|Cu cell afforded an ultrahigh Coulombic efficiency (CE) of 99.7%. Moreover, the Li|LFP cell with 4% additive exhibited high-capacity retention and better rate performance, especially at 5C. The additive 2,2,2-TFTF offers a nontraditional option for high-performance lithium metal batteries with simplicity and saving.

作为圣杯阳极，锂（Li）金属在开发下一代高能量密度电池方面引起了相当大的兴趣。然而，在锂电镀过程中，由于固体电解质界面（SEI）保护不佳而导致的锂枝晶在很大程度上限制了锂的应用。在这里，我们报道了一种有效的电解质添加剂，即三氟乙酸 2,2,2-三氟乙酯 (2,2,2-TFTF)，它通过 SEI 层的简单介导作为抑制锂枝晶生长的高效抑制剂。DFT计算和一系列表征结果表明，该添加剂极大地有利于在锂负极上形成更多的保护性SEI层和均匀的锂沉积。引人注目的是，添加 4% 的 Li|Li 电池具有 750 小时的长循环寿命，而 Li|Cu 电池提供了 99.7% 的超高库仑效率 (CE)。而且，添加 4% 添加剂的 Li|LFP 电池表现出高容量保持率和更好的倍率性能，尤其是在 5C 时。添加剂 2,2,2-TFTF 为高性能锂金属电池提供了一种非传统的选择，既简单又节省。