异氰酸酯抑制 LiTFSI电解液铝集流体腐蚀研究

IsocyanateInhibitstheCorrosionofAluminumCurrentCollector

中文关键词:  锂电池  异氰酸酯  双三氟甲烷磺酰亚胺锂  铝箔  腐蚀

英文关键词:Lithium battery  Isocyanate  Lithium bis(trifluoromethylsulphonyl)imide  Aluminum foil  Corrosion

中文摘要:

      商用锂电池普遍采用六氟磷酸锂(LiPF6)电解液，但其热稳定性差、易水解。相比之下，双三氟甲烷磺酰亚胺锂(LiTFSI)热稳定性好、不易水解，有望替代 LiPF6。然而， LiTFSI电解液对集流体铝箔腐蚀，阻碍了其大规模实际应用。通过添加适量异佛尔酮二异氰酸酯( IPDI)，有效解决了上述问题。研究表明， IPDI能够在铝集流体表面生成氮化铝(AlN)保护层，有效地抑制 LiTFSI电解液对铝箔的腐蚀。同时， IPDI的引入可有效提高电解液的氧化稳定性，拓宽电化学窗口。此外，添加适量 IPDI可改善 LiTFSI电解液与锂金属的兼容性，抑制锂枝晶生长，提高 Li/Cu沉积剥离库伦效率(CE)。更重要的是， IPDI的引入显著提升锂电池的循环性能和倍率性能， Li/LiFePO4电池充放电循环 400圈，容量保持率高达 98%。本工作为抑制 LiTFSI电解液对铝箔的腐蚀提供了新的设计思路和研究方向，能够促进 LiTFSI电解液的实际应用。

英文摘要:

      Lithium hexafluorophosphate(LiPF6)electrolyte is widely used in commercial lithium batteries，but it has poor thermal stability and is easy to hydrolyze. In contrast，Lithium bis(trifluoromethylsulphonyl)imide(LiTFSI)has good thermal stability andis stable to hydrolysis，whichis expected to replace LiPF6. However，the corrosion of current collector aluminum foil by LiTFSI electrolyte hinders its large-scale practicalapplication.Inthispaper，theabove problemswere effectively solvedby adding an appropriate amount of isophorone diisocyanate(IPDI). The results show that IPDI can form a protective layer of aluminum nitride(AlN)on the surface of aluminum current collector，which effectivelyinhibits the corrosion of aluminum foil by LiTFSI electrolyte. At the same time，the introduction of IPDI effectively improves the oxidationstabilityoftheelectrolyteandexpandstheelectrochemicalwindow.Inaddition，theappropriate amount of IPDI improves the compatibility of LiTFSI electrolyte with lithium metal，inhibits lithium dendrites，andimproves the stripping coulombic efficiency(CE)ofLi/Cu deposition. More importantly，the introduction of IPDI significantly improves the cycle performance and rate performance of lithium batteries. The capacity retention rate of Li/LiFePO4 battery is as high as 98% after 400 cycles. This work provides a new design idea and research direction for inhibiting the corrosionof aluminum foil.