New insights in the leaching kinetics of cathodic materials in acidic chloride media for lithium-ion battery recycling

Leaching reactions in hydrochloric acid of several cathodic materials used lithium-ion batteries were investigated between 25 °C and 82 °C. The dissolution rate increased as follows: NMC811 (LiNi0.8Mn0.1Co0.1O2) > NMC622 (LiNi0.6Mn0.2Co0.2O2) NMC532 (LiNi0.5Mn0.3Co0.2O2) NMC111 (LiNi1/3Mn1/3Co1/3O2). lithium is faster than that for nickel, cobalt manganese. Data analysis demonstrated NMC always a two-step process. In the first step, was transformed very quickly into new lithium-defficient phase. This phase subsequently dissolved during second-rate limiting step. No significant impact solid/liquid ratio on leaching kinetics observed far solid-liquid remained below stochiometric composition. Finally, shrinking core model first-order law to investigate second rate-limiting which main step involved digestion acid.