1. High-value utilization of recovered LiPF6 from retired lithium-ion batteries.
- Author
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Wang, Jie, Cui, Xiaoling, Song, Linhu, Zhu, Junlong, Wang, Yinong, Zong, Feifei, Zhang, Ningshuang, Zhao, Dongni, and Li, Shiyou
- Subjects
LITHIUM-ion batteries ,ELECTRIC vehicles ,LITHIUM ,RAW materials ,POLYELECTROLYTES ,WASTE recycling ,OXALATES - Abstract
With the large-scale retirement of new energy vehicles, it is particularly important to recycle and reuse retired lithium-ion batteries (LIBs). However, the current improper handling of spent electrolytes will cause serious environmental problems. Here, we propose a novel, simple and easy-to-implement method to realize the high-value utilization of recovered electrolytes from retired LIBs. Comparing with the initial content of LiPF
6 (1 mol L−1 in a mixed carbonate solvent system, and about 1 g in a 18650 type LIB) in fresh batteries, a maximum leaching efficiency of 29% could be realized during the full-component resource reclamation of retired LIBs, using the selective mixed leaching solvent system of dimethyl carbonate + CHClF2 (1 : 1, v/v ratio). Then the water and HF impurities are reduced from 80.90 ppm to 4.56 ppm and from 1312.91 ppm to 291.52 ppm by pre-treatment with hexamethyl disilazane (C6 H19 NSi2 ). Although the purified electrolyte does not meet the standards for re-use in LIBs, it can be used as a synthetic raw material for lithium salt additives. As a typical case, the LiPF6 salt in a leached electrolyte is recycled into a salt additive of lithium difluorodioxalate phosphate (LiDFBOP) under the preferred reaction conditions (75 °C, 27 h, with a molar ratio of 1 : 3 for LiPF6 : bis (trimethylsilicon)oxalate), realizing closed-loop recycling. The electrochemical results show that the electrochemical performances of the graphite/Li and LNCA/Li half cells are significantly improved with the addition of the as-prepared LiDFBOP additive. This research gives a large-scale synthesis route to realize high-value utilization of low-quality LiPF6 , and helps establish a full-component resource reclamation process of retired LIBs. It not only improves environmental friendliness, but also realizes the high efficiency utilization of resources. [ABSTRACT FROM AUTHOR]- Published
- 2024
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