Hydrometallurgical Processes for Recycling Spent Lithium-Ion Batteries: A Critical Review

The amount of spent lithium-ion batteries has grown dramatically in recent years, and the development of a recycling process for spent lithium-ion batteries is necessary and urgent from the viewpoints of environmental protection and resource savings. The hydrometallurgical process is considered to be the most suitable method for the recycling of spent lithium-ion batteries. The current status of hydrometallurgical recycling technologies of spent lithium-ion batteries is reviewed in this paper. A series of hydrometallurgical procedures including pretreatment of the spent lithium-ion batteries, leaching process and separation of valuable metals from leaching solution are introduced in detail, and their advantages and problems are analyzed. Finally, the prospects and direction of the recycling of spent lithium-ion batteries are put forward. It is pointed out that a more flexible and universal process is required for the recovery of different types of spent lithium-ion batteries. Besides cathode active materials, the other components of spent lithium-ion batteries including electrolyte and anode materials also need to be recovered due to their potential environmental hazards.