Recent and Novel Leaching Processes for Recovery of Metals from Spent Lithium-ion Batteries: A Review

In this review article, we have compiled state-of-the-art recent hydrometallurgical processes used to recover metals from spent lithium-ion batteries. The composition of lithium-ion batteries has evolved over time to fulfil the demand for storage capacity. Similarly, metal recovery and recycling strategies have evolved due to compositional changes and technological advancement. Traditional inorganic and organic acid leaching has various merits and limitations. Recent research has focused on creating enhanced leaching methods that incorporate cutting-edge techniques such as electrochemical, ultrasonic, and oxidative leaching. Alkaline, ammoniacal, and mechanochemical leaching have all been explored as pre-treatment methods. We have presented brief overviews on prospects of water leaching and combination of pyro-hydrometallurgical reduction roasting and leaching. Finally, we discussed the difficulties in the recovery process caused by the constantly changing compositions of next-generation batteries because of various factors. A data analytics-based framework is proposed as a promising solution for capturing and explaining the effects of various parameters by leveraging historical data to optimise process conditions.