Electrolyte is the key to improve the safety, cycle performance and temperature adaptation of lithium batteries. In this paper, we introduce a novel electrolyte that based on ionic liquids (ILs) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR₁₄-TFSI) and fluorinated solvent 1,1,1,3,3,3-hexafluoroisopropyl methyl ether (HFPM). HFPM can significantly reduce the viscosity of PYR₁₄-TFSI and enhance the wettability with Celgard separators. In addition, the coordination of PYR₁₄-TFSI and HFPM promotes the local dissolution of lithium nitrate and helps to form a stable cathode/anode interface film. The electrochemical test shows that the electrochemical window of the electrolyte can reach to 5.35 V. For the Li/LiNi_0.6Co_0.2Mn_0.2O₂ half cells, the capacity retention is 94% and the Coulomb efficiency is 99.9% after 100 cycles at 0.5 C. The uniform and dense interface film is characterized and confirmed by scanning electron microscopy and X-ray photoelectron spectroscopy, etc. Furthermore, the half-cell also exhibits good thermal stability at high temperature. Considering ILs and fluoroether are non-flammable solvent, this work may pave the way for designing future generation high-performance electrolyte for lithium batteries.

电解质是提高锂电池安全性，循环性能和温度适应性的关键。在本文中，我们介绍了一种基于离子液体（IL）1-丁基-1-甲基吡咯烷鎓双（三氟甲基磺酰基）酰亚胺（PYR ₁₄ -TFSI）和氟化溶剂1,1,1,3,3,3-的新型电解质六氟异丙基甲基醚（HFPM）。HFPM可以显着降低PYR ₁₄ -TFSI的粘度，并增强Celgard隔膜的润湿性。此外，PYR ₁₄ -TFSI和HFPM的配位促进了硝酸锂的局部溶解，并有助于形成稳定的阴极/阳极界面膜。电化学测试表明，电解质的电化学窗口可以达到5.35V。对于Li / LiNi _0.6 Co_0.2 Mn _0.2 O ₂半电池，在0.5 C下经过100次循环后，容量保持率为94％，库仑效率为99.9％。均匀且致密的界面膜的特征在于通过扫描电子显微镜和X射线光电子能谱等进行表征和确认。此外，半电池在高温下也表现出良好的热稳定性。考虑到IL和氟醚是不可燃溶剂，这项工作可能为设计下一代锂电池高性能电解质铺平道路。