A comprehensive review and classification of unit operations with assessment of outputs quality in lithium-ion battery recycling

Lithium-ion batteries (LIBs) are the core component of the electrification transition, being used in portable electronics, electric vehicles, and stationary energy storage. The exponential growth of LIB use generates a large flow of spent batteries which must be recycled. This paper provides a comprehensive review of industrial realities of LIB recycling companies in Europe, North America, and Asia. An in-depth description of representative pyrometallurgy-based and hydrometallurgy-based processes is reported, providing classification of unit operations, their industrial readiness, and quality of output materials. The analysis shows that the pyrometallurgical route can treat different LIB chemistries without pre-sorting, but Li is not recovered unless the slag is refined. Hydrometallurgy-based processes are more chemistry-specific and in, although being affected by losses of electrode active materials during the mechanical pre-treatments for black mass separation. Efforts are required to promote in Europe the industrial capacity and readiness of hydrometallurgical processes by facilitating sorting and mechanical separations. There is also the need for harmonization of criteria for outputs definitions and rules for calculating recycling efficiency indicators. This represents an opportunity for modeling to support quantitative techno-economic and environmental assessments of the entire LIB recycling chain.