A Novel Green Process for Recovery of Transition Metal Ions from Used Lithium-ion Batteries by Selective Coordination of Ethanol

As the abundance of end-of-life lithium-ion batteries continues to increase, it is significant to recover valued metals in an eco-friendly way, yet this remains a challenge. Based on a novel deep eutectic solvent (DES) consisting of betaine hydrochloride and lactic acid, we developed a combined DES–ethanol selective separation process for extracting valuable metals from spent LiCoO2 batteries, with a high efficiency. This process accomplished the complete leaching of lithium-ion battery (LIBs) cathode materials by DES. The selective separation of lithium and cobalt was accomplished by changing the coordination environment of transition metal ions in DES using ethanol. The strategy was also applicable to LiNixCoyMn1–x–y batteries with different compositions and efficiently achieved stepwise transition metal separation. Further, we analyzed in depth the detailed selective extraction mechanism. This green and high-efficiency recycling process is a promising candidate for recovering valuable metals from used LIBs. The proposed method is particularly attractive due to its high selectivity, considerable economic advantages, and environmental benefits.