Separation strategies of metals from black mass leaching solution of lithium-ion batteries

Lithium-ion batteries (LIBs) have achieved rapid development and widespread application over the past few decades due to their excellent performance. However, limited by their service life, a large number of spent LIBs are in urgent need of recycling. Among the various recycling methods, hydrometallurgy is an effective approach, which produces the black mass leaching solution (BMLS) of batteries. Nevertheless, the complex composition and diverse types of metals in BMLS make the separation of metals quite challenging. As such, developing a green, efficient and low-cost separation method in BMLS is imperative to recycle LIBs and establish a sustainable lifecycle. This review first summarizes four common separation methods, then describes the extraction methods for different metals according to their types (e.g., Cu, Fe, Al, Ni, Co, Mn and Li), and finally summarizes the typical process flowcharts and provides an outlook on future research directions.