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Efficient Separation of Aluminum Foil and Cathode Materials from Spent Lithium-Ion Batteries Using a Low-Temperature Molten Salt

Wang, Mengmeng, Tan, Quanyin, Liu, Lili, Li, Jinhui
ACS sustainable chemistry & engineering 2019 v.7 no.9 pp. 8287-8294
aluminum, aluminum foil, cathodes, heat, lithium batteries, melting, peeling, recycling, temperature
The effective separation of aluminum (Al) foil and cathode materials is a critical issue for the recycling of spent lithium-ion batteries (LIBs). Previous studies have shown that the strong binding force provided by the organic binder polyvinylidene fluoride (PVDF) between the cathode materials and the Al foil of spent LIBs makes it difficult to peel off the cathode materials from the Al foil, reducing the effectiveness of the metal recovery process. This study reports on a low-temperature molten salt technology for melting the organic binder PVDF. The results showed that an aluminum chloride-sodium chloride (AlCl₃-NaCl) system—a nontoxic reaction medium—could melt PVDF efficiently and is environmentally friendly as well, because of the phase transformation of molten salt caused by heat storage. The optimal conditions for peeling off cathode materials were a temperature of 160 °C, molten salt:cathode electrode mass ratio of 10:1, and holding time of 20 min. The highest peeling off percentage of cathode materials was 99.8 wt %. The purpose of this study was to provide an environmentally friendly, low-cost, and effective solution for the separation of cathode materials and Al foil from spent LIBs.