Direct production of cathode active material from black mass of spent lithium nickel manganese cobalt oxide batteries: Integrating and optimizing Li2CO3 recovery for enhanced economic and environmental performance

The growing demand for lithium-ion batteries (LIBs) highlights the need for efficient lithium recovery. Developing cost-effective, environmentally friendly extraction methods from secondary sources, such as end-of-life (EoL) Li-ion batteries, is essential for a sustainable lithium supply chain. This study optimizes Li2CO3 recovery, ensuring battery-grade quality, seamless integration into cathode active material (CAM) synthesis, and economic feasibility within hydrometallurgical recycling. Two approaches for single-stage Li recovery in a hydrometallurgical process with integrated CAM production from black mass of lithium nickel manganese cobalt oxide (NMC) LIBs are compared: homogeneous precipitation with Na2CO3 and heterogeneous precipitation using CO2 gas. The analysis focuses on process efficiency, Li purity, and suitability for battery applications. Results show that selective CO2-based precipitation demonstrated higher selectivity, achieving 97.10 % Li recovery (recoverable as Li2CO3), compared to 77.97 % for Na2CO3 precipitation, with both methods yielding batterygrade purity and morphology. Recycled NMC622 cathodes synthesized from recovered Li2CO3 achieved over 95 % of the discharge capacity of those from commercial Li2CO3. Recycled materials demonstrated excellent capacity retention and high coulombic efficiency (~100 %) after 30 cycles. Full-scale modeling assessed economic and environmental impacts in European LIBs recycling scenarios. Heterogeneous precipitation showed higher profitability (+0.73 M€/year) and greater net GHG reduction (986 t CO2/year) but was more energy price-sensitive. Homogeneous precipitation demonstrated stable profitability (+0.62 M€/year); however, reduction in GHG emissions was more limited, reaching 518 t CO2/year. This study integrates lithium recovery and water reclamation into a closed-loop process, enabling direct NMC cathode production, offering a sustainable and economically viable solution for LIBs manufacturing.