Sustainable Lithium Recovery From Spent NMC622 Cathodes by a CO 2 ‐Leaching Pathway

ABSTRACT The growing demand for lithium‐ion batteries (LIBs) coupled with the need for sustainable end‐of‐life strategies, highlights the importance of developing environmentally benign hydrometallurgical recovery routes. This work investigates a CO 2 ‐based leaching route as a selective and efficient approach for Li recovery from NMC 622 cathode material. The leaching mechanism was systematically examined by varying the temperature, pressure, liquid‐to‐solid ratio, reaction time, and stirring speed to characterize their influence on Li dissolution. The optimized operating window (1 h, 220°C, 110 mL g −1 , 35 bar, and 500 rpm) yields a Li extraction efficiency of 98.81 ± 1.37%, demonstrating the high selectivity of CO 2 ‐driven leaching toward lithium over transition metals. Lithium was subsequently recovered as lithium carbonate (Li 2 CO 3 ) through controlled rotary evaporation, with 50°C identified as the most energy‐efficient crystallization temperature. Structural characterization by SEM and XRD verified the formation of well‐crystallized Li 2 CO 3 suitable for further processing for the manufacturing of new cathodes. Furthermore, a feasibility assessment demonstrates that, alongside significant internal energy optimizations, the method achieves an exceptionally low chemical operating expenditure (OPEX) and avoids the generation of hazardous acidic wastewater compared to traditional recycling strategies. Collectively, the results indicate that CO 2 ‐based hydrometallurgical leaching constitutes a promising and resource‐efficient strategy for lithium recovery from spent LIBs, offering reduced chemical consumption, strong selectivity, and lower energy requirements compared with conventional leaching routes.