Realizing the reusability of leachate for the hydrometallurgical recycling of spent lithium cobalt oxide by dynamically regulating the solubility product

Abstract

The rapidly increasing amount of spent lithium-ion batteries (LIBs) requires recycling technology with higher economic and environmental efficiency, while current hydrometallurgical recycling strategies usually consume large amounts of inorganic acids and reducing agents without reusability of the leachate due to the addition of precipitants. Herein, we report a precipitant-free and closed-loop strategy for recycling lithium cobalt oxide (LCO) where the extraction of metal elements from dissolved leachate is realized by dynamically regulating the solubility product (K_sp). A choline chloride : oxalic acid (ChCl : OA) type deep eutectic solvent (DES) has been demonstrated as the leachant while the cobalt and lithium can be recovered by either controlling the complexing process or cooling, thus achieving controlled precipitation of elements without adding precipitants, and thereby maintaining the structure of the leachate to the largest extent and realizing reusability. The strategy based on the dynamic regulation of K_sp is expected to provide a general method for designing a reusable leachant for the hydrometallurgical recycling of the electrodes of spent LIBs.