A review on spent lithium-ion battery recycling: from collection to black mass recovery

The advent of lithium-ion battery technology in portable electronic devices and electric vehicle applications results in the generation of millions of hazardous e-wastes that are detrimental to the ecosystem. A proper closed-loop recycling protocol reduces the environmental burden and strengthens a country with resource sustainability, circular economy, and the provision of raw materials. However, to date, only 3% of spent LIBs have been recycled. The recycling efficiency can be further increased upon strong policy incentives by the government and legislative pressure on the collection rate. This review sheds light on the pretreatment process of end-of-life batteries that includes storage, diagnosis, sorting, various cell discharge methods (e.g., liquid medium, cryogenic and thermal conditioning, and inert atmosphere processing), mechanical dismantling (crushing, sieving, sequential, and automated segregation), and black mass recovery (thermally and solvent leaching). The advantage of the stagewise physical separation and practical challenges are analyzed in detail. Disassembling the battery module pack at the cell level with the improved technology of processing spent batteries and implementing artificial intelligence-based automated segregation is worth it for high-grade material recovery for battery applications. Herein, we outline an industry-viable mechanochemical separation process of electrode materials in a profitable and ecofriendly way to mitigate the energy demand in the near future. The advent of lithium-ion battery technology in portable electronic devices and electric vehicle applications results in the generation of millions of hazardous e-wastes that are detrimental to the ecosystem.