Selective Recovery of Cobalt and Nickel from Spent Lithium-Ion Battery NMC Cathodes Using a Hydrophobic Deep Eutectic Solvent
Nadirov R. Kamunur K. Mussapyrova L. Batkal A. Tyumentseva O.
October 2025Multidisciplinary Digital Publishing Institute (MDPI)
Metals
2025#15Issue 10
A hydrophobic deep eutectic solvent (HDES) composed of Aliquat 336, decanoic acid, and n-hexanol, diluted with kerosene, was investigated for the selective leaching of LiNi0.33Mn0.33Co0.33O2 (NMC-111) cathode materials. While conventional choline chloride-based DESs co-dissolve Li and transition metals almost completely, the present HDES–acid hybrid system deliberately sacrifices maximum recovery to achieve selectivity. In combination with a low concentration of H2SO4, the HDES enabled preferential dissolution of Co and Ni (~84% and ~80% after 6 h at 90 °C, respectively), while Li and Mn largely remained in the solid residue (>93%). Kinetic modeling indicated that the process is controlled by a surface chemical reaction with apparent activation energies of ~~49 kJ mol−1 (for Ni recovery) and ~51 kJ mol−1 (for Co recovery). The leaching residues were enriched in stable Li-Mn-O phases in a way that offers a basis for stepwise recovery. These findings show that hydrophobic eutectic media coupled with mild acid activation provide a sustainable pathway for the selective recycling of LIB cathodes.
cobalt and nickel recovery , hydrophobic deep eutectic solvents (HDES) , lithium-ion batteries (LIBs) , selective leaching
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Institute of Combustion Problems, Almaty, 050012, Kazakhstan
Faculty of Chemistry and Chemical Technology, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Institute of Combustion Problems
Faculty of Chemistry and Chemical Technology
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