Rechargeable lithium batteries based on lithium metal anodes and high-nickel cathodes have unparalleled advantages in energy density. However, the massive growth of lithium dendrites and the rapid degradation of high-nickel ternary oxides in commercial electrolyte have greatly hindered their application. To circumvent this issue, we design a series of analogs as electrolyte additives by adopting acetyls as connecting units to splice multiple functional groups. Among these additives, N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) stands out due to the rational molecular configuration and the synergistic complementarity of amide, trifluoromethyl and trimethylsilyl groups. The cycling reversibility of the lithium metal anode (1050 h at 1 mA cm⁻¹ to 1 mAh cm⁻¹) and the capacity retention of the LiNi_0.9Co_0.05Mn_0.05O₂ cathode (85.9 % at 3–4.3 V after 300 cycles) in MSTFA modified carbonate electrolyte are tremendously enhanced. In addition, the safety of the battery and the tolerance to harsh working conditions (high & low temperature, high-voltage) are also ameliorated. This work sheds light on the relationship between structure and activity of molecules as well as provides a novel idea for modular design of additives.

基于锂金属阳极和高镍阴极的可充电锂电池在能量密度方面具有无可比拟的优势。然而，商业电解液中锂枝晶的大量生长和高镍三元氧化物的快速降解极大地阻碍了它们的应用。为了规避这个问题，我们设计了一系列类似物作为电解质添加剂，采用乙酰基作为连接单元拼接多个官能团。在这些添加剂中，N-甲基-N-(三甲基甲硅烷基)三氟乙酰胺(MSTFA)因其合理的分子构型和酰胺、三氟甲基和三甲基甲硅烷基的协同互补性而脱颖而出。锂金属负极的循环可逆性（1050 h at 1 mA cm ^-1 to 1 mAh cm ^-1_{) 和 LiNi 0.9} Co _0.05 Mn _0.05 O ₂正极（300 次循环后在 3–4.3 V 下为 85.9%）在 MSTFA 改性碳酸盐电解质中的容量保持率得到极大提高。此外，电池的安全性和对恶劣工作条件（高低温、高压）的耐受性也得到改善。这项工作阐明了分子结构和活性之间的关系，并为添加剂的模块化设计提供了一种新思路。