Conversion Mechanisms of Selective Extraction of Lithium from Spent Lithium-Ion Batteries by Sulfation Roasting

With the undergoing unprecedented development of lithium-ion batteries (LIBs), the recycling of end-of-life batteries has become an urgent task considering the demand for critical materials, environmental pollution, and ecological impacts. Selective recovery of targeted element(s) is becoming a topical field that enables metal recycling in a short path with highly improved material efficiencies. This research demonstrates a process of selective recovery of spent Ni-Co-Mn (NCM)-based lithium-ion battery by systematically understanding the conversion mechanisms and controlling the sulfur behavior during a modified-sulfation roasting. As a result, Li from complex cathode components can be selectively extracted with high efficiency by only using water. Notably, the sulfur driven recovery processes can be divided into two stages: (i) part of the structure of NCM523 was destroyed, and Ni, Co, and Mn were reduced to divalent in different degrees to form sulfate (NiSO