Sustainable Recovery of Critical Metals from Spent NCM Cathodes with an Aminosugar-Based Deep Eutectic Solvent

The increasing generation of spent lithium-ion batteries (LIBs) necessitates the development of sustainable recycling technologies for critical metals. In this study, a novel aminosugar-based deep eutectic solvent (DES) composed of glucosamine hydrochloride (GlcN·HCl) and betaine hydrochloride (Betaine HCl) was developed for the simultaneous recovery of cobalt (Co), lithium (Li), manganese (Mn), and nickel (Ni) from spent nickel–cobalt-manganese (NCM) cathode materials. Systematic screening identified this DES as highly efficient under mild conditions. Under the optimized parameters (HBD/HBA ratio of 1:2, solid-to-liquid ratio of 0.01 g·g –1, temperature of 80 °C, and leaching time of 80 min), leaching efficiencies of 100% for Co, 98.98% for Li, 99.11% for Mn, and 100% for Ni were achieved. Kinetic analysis based on the shrinking core model indicated that the leaching process is controlled by surface chemical reactions, with apparent activation energies of 53.43–62.94 kJ·mol –1 . Spectroscopic characterization and electronic structure analysis revealed that extensive hydrogen bonding, strong polarity, and favorable frontier molecular orbitals synergistically promote metal–oxygen bond disruption and stabilize dissolved metal species. This work highlights aminosugar-based DES as a green and effective platform for NCM cathode recycling.