Full recovery of lithium salts and transition metal oxides from spent ternary cathode lithium-ion batteries

This study developed a novel deep eutectic solvent (DES) composed of tetraethylammonium chloride and oxalic acid for efficient recovery of valuable metals from spent lithium-ion battery ternary cathode materials. The DES selectively leached Li, Co, and Mn, while precipitating Ni as high-purity NiC₂O₄·2H₂O. The addition of H₂O₂ reduced the consumption of oxalic acid and enhanced metal leaching under mild conditions. By modulating the coordination environment and leveraging solubility differences, single metal compounds with purities exceeding 97% have been isolated, which are applicable for resynthesizing high-performance cathode materials.