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

• Published in: Hydrometallurgy 2021-09, Vol.204, p.105705, Article 105705
• Main Authors: Xuan, Wen, de Souza Braga, Antônio, Korbel, Chloé, Chagnes, Alexandre
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Hydrochloric acid; Kinetics; Leaching; Lithium-ion batteries; NMC; Recycling
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2021.105705

Leaching reactions in hydrochloric acid of several cathodic materials used in 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). The dissolution of lithium is faster than that for nickel, cobalt and manganese. Data analysis demonstrated that NMC dissolution is always a two-step process. In the first step, NMC was transformed very quickly into a new lithium-defficient phase. This phase was subsequently dissolved during a second-rate limiting step. No significant impact of the solid/liquid ratio on the leaching kinetics was observed as far as the solid-liquid ratio remained below the stochiometric composition. Finally, a shrinking core model and a first-order rate law were used to investigate the leaching kinetics of the second rate-limiting step, which is the main step involved during NMC digestion in hydrochloric acid. •The stoichiometry of NMC electrodes influence the leaching kinetics.•The leaching mechanism involve two step.•The first step is responsible for high lithium dissolution rate.•The second step involving redox reaction is the limiting step.•Two leaching models have been developed to describe leaching kinetics.