Mechanism of aluminum corrosion in LiFSI-based electrolyte at elevated temperatures

• Published in: Transactions of Nonferrous Metals Society of China 2021-05, Vol.31 (5), p.1439-1451
• Main Authors: LI, Chun-lei, ZENG, Shuang-wei, WANG, Peng, LI, Zhao-juan, YANG, Li, ZHAO, Dong-ni, WANG, Jie, LIU, Hai-ning, LI, Shi-you
• Format: Article
• Language: English
• Subjects: corrosion inhibition; elevated temperatures; interfacial film; LiFSI-based electrolyte; lithium bis(oxalate)borate (LiBOB); lithium-ion batteries
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(21)65588-7

Lithium bis(fluorosulfonyl)imide (LiFSI) is a promising replacement for lithium hexafluorosphate due to its excellent properties. A solution to the corrosion of aluminum (Al) current collectors by LiFSI at elevated temperatures is essential. The mechanisms of Al corrosion in LiFSI-based electrolyte at 45 °C were studied with density functional theory calculations and spectroscopic investigations. It is found that the irregular, loose and unprotected AlF3 materials caused by the dissolution of co-generated Al(FSI)3 can exacerbate Al corrosion with the increase of temperature. Lithium bis(oxalate)borate (LiBOB) can effectively inhibit the Al corrosion with a robust and protective interphase; this can be attributed to the interfacial interactions between the Al foil and electrolyte. Boron-containing compounds promote the change from AlF3 to LiF, which further reinforces interfacial stability. This work allows the design of an interface to Al foil using LiFSI salt in lithium-ion batteries.