Selective lithium extraction from spent LiNi_xCo_yMn_zO₂powder based on S, N synergistic assisted subcritical water system

With the explosive growth in demand for lithium-ion batteries (LIBs), the recycling of the valuable metal components in them has become particularly important. However, in the previous recycling of spent LIBs, lithium is easily lost resulting in wasted resources. In this paper, a new simple and efficient selective lithium extraction strategy is developed, which uses a thiourea-assisted subcritical water system to achieve preferential extraction of lithium from spent LIBs. Due to the enhancement of the lithium extraction process by subcritical water and the synergistic effect of S and N in thiourea on the spent LiNixCoyMnzO2 (NCM) cathode powder, 99.9% of lithium is selectively leached into water. Meanwhile, the transition metals (Ni, Co and Mn) in the leaching residue can be leached out by dilute acid, and the corresponding leaching rates are 99.8%, 99.7%, and 99.9%, respectively. In addition, LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode material with good electrochemical performance is successfully regenerated. The process has been economically and environmentally assessed as greatly simplifying the recycling process and establishing a highly efficient recycling route for spent LIBs with low environmental impact.