A comprehensive review on the separation and purification of valuable metals from the leachate of spent lithium-ion batteries

In recent years, the rapid expansion of the lithium-ion battery (LIB) market has led to a shortage of precious metal resources and the accumulation of waste LIBs. From the perspectives of resources, economics, environment, and human health, more research must be dedicated to the recycling of LIBs. The separation and purification process, as the final and crucial step in hydrometallurgy, plays a decisive role in determining whether LIBs can be sustainably recycled. Considering the current lack of comprehensive reviews on separation and purification techniques, this paper systematically summarizes the work on the separation and purification of hydrometallurgical leachates from LIBs, focusing on different battery types, separation principles, and leachate compositions. The key technologies discussed include chemical precipitation, solvent extraction, adsorption separation, and electrodeposition. Furthermore, the paper provides an evaluation and outlook on these techniques. The objective of this study is to offer a systematic overview of the laboratory research on separation and purification processes in the hydrometallurgical recycling of waste LIBs, with the aim of providing reasonable and effective references for the future application of these processes.