Efficient\nand Prioritized Lithium Recovery from Spent\nLi(Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>)O<sub>2</sub> Cathodes\nvia SO<sub>2</sub> Treatment

With the wide application of ternary lithium-ion batteries,\nthe\nincreased usage of batteries has resulted in a corresponding rise\nin the amount of discarded batteries. Here, we propose an efficient\nand prioritized lithium extraction process with a low environmental\nimpact for the recovery of valuable metal components from spent LiNi<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>O<sub>2</sub> cathode materials.\nSO<sub>2</sub> calcination–water leaching was used to recover\nLi, while H<sub>2</sub>SO<sub>4</sub> acid leaching facilitated the\nrecovery of Ni, Co, and Mn, yielding a precursor solution for the\ntreatment of discarded NCM batteries. The effects of calcination temperature,\ncalcination time, water leaching time, water leaching liquid–solid\nratio, different battery ratios, acid leaching time, acid leaching\nliquid–solid ratio, and acid leaching temperature were optimized.\nThe acid leaching process was controlled by surface chemical reactions\nthrough kinetic analysis. Under optimal conditions, Li was converted\nto soluble Li<sub>2</sub>SO<sub>4</sub>, achieving an impressive leaching\nrate of 99.7%. Ni, CO, and Mn were converted to their respective oxides.\nFurthermore, it was demonstrated that the formation of Li<sub>2</sub>Mn(SO<sub>4</sub>)<sub>2</sub> from Mn with Li during calcination\nenhances the leaching efficiency across different battery composition\nratios. The activation energies of Ni, Co, and Mn during the acid\nleaching process were determined by kinetic calculations, yielding\nvalues of 130.19, 133.05, and 134.09 kJ mol<sup>–1</sup>, respectively.\nThis study provides a novel method for recycling spent NCM cathode\nmaterials.