Sulfuric Acid-Based Leaching for Purification of Ni-Co Recovered from Pyrometallurgically Recycled Spent Lithium-Ion Batteries

Lithium-ion batteries (LIBs) are increasingly used in electric vehicles (EVs) and energy storage systems (ESSs), with high energy density LiNixCoyMn1−x−yO2 (NCM) widely adopted as an EV cathode material. Carbothermic pyrometallurgical recycling has attracted considerable attention because it enables large-scale treatment of whole battery cells without the need for additional additives and pre-treatment. However, studies on purification of Ni-Co products generated during the process remain limited. In this study, a sulfuric acid-based selective leaching process was developed to selectively remove impurity phases and of Al-containing NCM cathode materials, enhancing the purity and recovery efficiency of nickel and cobalt from the spent lithium-ion batteries. The results indicate that the optimized leaching process effectively increases the concentration of nickel and cobalt, achieving a remarkable reduction of contaminating elements, with purification rates surpassing 95% for the recovered metals. This innovative approach not only contributes to the sustainable recycling of valuable resources from LIBs but also promotes environmentally friendly practices in the recycling industry.