Corrosion/passivation of aluminum current collector in bis(fluorosulfonyl)imide-based ionic liquid for lithium-ion batteries
2012; Elsevier BV; Volume: 22; Linguagem: Inglês
10.1016/j.elecom.2012.05.018
ISSN1873-1902
AutoresErang Cho, Junyoung Mun, Oh B. Chae, Oh Min Kwon, Hyung‐Tae Kim, Ji Heon Ryu, Young Gyu Kim, Seung M. Oh,
Tópico(s)Ionic liquids properties and applications
ResumoThe corrosion behavior of aluminum foil that is used as the positive current collector for lithium-ion batteries is studied in N-methyl-N-propyl-pyrrolidinium bis(fluorosulfonyl)imide (PMPyr-FSI), which is considered as a highly attractive solvent due to a very low viscosity. This work reports that FSI anion is corrosive for aluminum foil upon anodic polarization (> 4.0 V vs. Li/Li+). The pitting corrosion is, however, greatly reduced by adding lithium hexafluorophosphate (LiPF6). The anion of the salt is known to be a corrosion inhibitor for aluminum. It likely reacts to generate hydrofluoric acid that then attacks the native aluminum oxide (Al2O3) to produce a strong passivation layer comprising aluminum fluoride (AlF3). Resultantly, the high rate capability, which is the potential merit achievable by using the FSI-containing ionic liquid solvent, can be implemented with a LiCoO2 positive electrode.
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