Hydration equilibrium-controlled cation–anion coordination competition for precise recovery of all valuable metals from spent lithium-ion batteries

The selective recovery of metals from spent lithium-ion batteries (LIBs), particularly from Ni-based ternary (NCM) cathode materials, is a significant challenge due to their complex elemental composition. Herein, we present a novel, sustainable method that addresses the limitations of traditional techniques, which often rely on extractants or precipitants for metal separation. By precisely controlling the temperature and H₂O content in deep eutectic solvents (DESs), we achieve efficient and selective recovery of Ni, Li, Co, and Mn, with recovery efficiencies >94% and product purities >97%, all without the need for additional chemicals. Additionally, the used DES can be regenerated by evaporating H₂O and replenishing reagents, enhancing both sustainability and cost-effectiveness. A successful scale-up in a 10 L reaction unit validates the industrial feasibility of the process. This work presents a major advancement in the sustainable recycling of spent LIBs, offering a practical and eco-friendly solution for efficient multi-metal separation and resource recovery. © The Royal Society of Chemistry 2025.