Characterization of Thecnical KPIs in Material Recovery Processes for Spent Li-Ion Batteries As society transitions to greener energy solutions and reduces its consumption of primary raw materials, evaluating alternative strategies becomes increasingly important, especially for lithium-ion batteries. The use of these batteries is increasing sharply, and several recycling methods have been developed, with pyrometallurgy and hydrometallurgy being the most prominent. This study focuses on the latter. A detailed literature review was conducted to examine previous work related to hydrometallurgical recycling. The review covers the entire process—from pretreatment and black mass production (the fine powder derived from spent batteries) to filtration steps—and the technical and environmental KPIs that earlier studies have investigated.