Recent advance in attractive pyrometallurgical recovery of electrode materials in spent lithium ion batteries: a review

With the development of energy storage technology, lithium-ion batteries (LIBs) occupy an increasing share in the energy storage field. Due to the expansion of the range of LIBs and the defects of LIBs themselves, the number of spent LIBs has increased dramatically. The core of LIBs recycling is the recovery of electrode materials. The pyrometallurgical recovery method, with the advantages of high reaction rate, large processing capacity, high recovery, direct use for purification and extraction of metals, technology simplicity, adaptability and mature industrialization technology, has become one of the important methods to recover electrode materials. In this paper, the pyrometallurgical process is reviewed in four aspects (reduction roasting, sulfide roasting, chlorination roasting and pyrolysis), focusing on the advantages and disadvantages of each aspect. It is noteworthy that the first three systems achieve high metal recovery. However, the residues of solid reducing agent in the reduction roasting system will affect the recovery of subsequent products. Equipment corrosion and environmental protection issues in sulfide roasting systems are of concern. Chlorination roasting systems have a great potential for recovery owing to the low cost and high chemical activity of the chlorinating agent, but problems of safety and corrosion remain to be solved. The recovery of hazardous pyrolysis gases can be achieved by alkaline washing and ice bath processes. Combining the advantages of existing technologies, an environmentally friendly, high-efficiency and low-cost electrode material recycling process is proposed. This paper is expected to provide a reference for the future development of the pyrometallurgical recovery process of spent LIBs.