A sustainable raw chemical process for metal recovery from unsorted spent lithium-ion batteries

Lithium-ion batteries (LIBs) are the leading technology for energy storage and for decarbonizing transport, but their rapid growth raises concerns about the demand for critical raw materials and end-of-life management. The EU has updated its list of critical and strategic materials—lithium, cobalt, copper, nickel, natural graphite—and set ambitious recycling targets, including recovering 80% of lithium and 95% of cobalt by 2031.[1] Current European recycling is dominated by pyrometallurgical routes, which require high temperatures, emit significant greenhouse gases, cannot recover lithium or aluminum, and generate harmful byproducts. Hydrometallurgical alternatives have advanced, but few have reached pre-industrial scale due to challenges such as safe battery deactivation, limited recovery efficiency, and dependence on cathode chemistry. Most studies address isolated steps and use sorted batteries, unlike real mixed waste streams.[2] A complete laboratory-scale hydrometallurgical process, that overcomes these limitations and is compatible with major LIB chemistries (LCO, NMC, NCA, LFP) without sorting, will be presented. Safe deactivation is achieved through discharge in a conductive medium (brass shreds), whose temperature profile shows improved safety over liquid-nitrogen or saline methods. A mild leaching solution of formic and hydrochloric acids achieves efficiencies comparable to strong acids. Metals are recovered by selective precipitation: lithium is isolated via sulfide addition and converted to carbonate with 85% efficiency and 97% purity; cobalt, nickel, and others yield high-purity sulfate solutions.[3] A life-cycle assessment shows a strongly negative environmental burden, driven by avoided impacts from recovering current collectors and metal salts, guiding future optimization.