Deep Eutectic Solvent-Driven Separation of Cathode Materials from Spent Lithium-Ion Batteries

The recycling of spent lithium-ion batteries (LIBs) is essential for the sustainable development of the new energy industry. A crucial first step in this process is the effective separation of the cathode materials from Al foil. In this work, based on the newly developed deep eutectic solvent (DES), we propose a novel mechanism in which hydrogen bonding drives carbonate solvation, leading to the activation of propylene glycol and subsequent dehydrofluorination of PVDF, thereby achieving efficient cathode-Al foil separation. Experimental results show that the separation efficiency exceeds 98%. Specifically, the potassium alkoxide generated in the DES promotes PVDF degradation that forms unsaturated organic compounds containing C=C bonds and fixes the F element as metal fluorides. Moreover, the structural integrity of both the cathode materials and Al foil remains well-maintained with negligible dissolution of transition metals and Al during the process. This strategy offers a promising, green, and efficient method for the separation of cathode materials from spent LIBs.