Separation and Comprehensive Recovery of Cobalt, Nickel, and Lithium from Spent Power Lithium-Ion Batteries

The popularization of electric vehicles drives the extensive use of power lithium-ion batteries (LIBs) and their abandonment after retirement. Spent power LIBs have a high economic value because they contain valuable metals which need to be recovered. In this study, the separation and comprehensive recovery of valuable metallic elements, including Co, Ni, and Li, from spent power LIBs were realized by a hydrometallurgical process of "calcination-leaching-synergistic extraction-synthesis". The results showed that, under the optimal conditions, the extraction efficiencies of impurities, such as Al and Cu, by P204 were 91% and 90%, respectively. A P507-N235 synergistic system was proposed to extract Co over Ni and Li with the maximum synergistic coefficient of 12.6. The extraction efficiency of Co, Ni, and Li was 99.5%, 3.9%, and 9.7%, respectively, and the separation coefficients of beta(Co/Ni) and beta(Co/Li) were 200.6 and 300.3, respectively. Cobalt oxalate, nickel oxalate, and lithium carbonate were finally obtained. Comprehensive recovery of valuable metals was realized, and the total recovery efficiency of Li, Ni, and Co was 84.1%, 93.1%, and 96.5%, respectively. This study provides positive significance for the improvement of cobalt extraction technology and comprehensive recycling efficiency of spent power LIBs.