A review of recycling spent lithium-ion battery cathode materials using hydrometallurgical treatments

With the increasing market share of lithium-ion battery in the secondary battery market and their applications in electric vehicles, the recycling of the spent batteries has become necessary. The number of spent lithium-ion batteries grows daily, which presents a unique business opportunity of recovering and recycling valuable metals from the spent lithium-ion cathode materials. Various metals including cobalt, manganese, nickel, aluminum, and lithium can be extracted from these materials through leaching with chemicals such as hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), oxalate (H2C2O2), DL-malic acid (C4H5O6), citric acid (C6H8O7), ascorbic acid (C6H8O6), phosphoric acid (H3PO4) or acidithiobacillus ferrooxidans. This paper provides a comprehensive review on the available hydrometallurgical technologies for recycling spent lithium-ion cathode materials. The recycling processes, challenges and perspectives reported to date and recycling companies in the market are summarized. To accelerate the development of battery recycling technology toward commercialization, some potential research directions are also proposed in this paper.