Green conversion of spent lithium-ion batteries via infrared pyrolysis: gas-assisted metal recovery and reaction pathway elucidation

Abstract

The recycling of waste lithium-ion batteries (LIBs) plays a pivotal role in the sustainable advancement of renewable energy technologies. This study presents a new technique for the ex situ recovery of cobalt and lithium by infrared rapid heating, using low-rank coal and biomass as precursors for the construction of reductive atmospheres. Rapid pyrolysis with infrared heaters can pyrolyze organic precursors at high temperatures in less than 30 seconds for an instantaneous high-volume gas supply. It facilitates the efficient recovery of Li₂CO₃ and CoO while extracting valuable oils with a lithium extraction rate of 98%. Compared to conventional techniques, the method minimized the interference of carbon and organic volatiles and achieved precise temperature control of pyrolysis and reduction processes. Besides, the effects of pyrolysis and reduction temperature on final products were investigated, and the reducing gas consumption and side reactions in the complex gas recovery process were obtained using an ex situ approach. In addition, the influence of cobalt with different crystalline structures on the reduction reaction due to catalytic Fischer–Tropsch synthesis is explored. This work represents a potentially versatile method for efficient pyrometallurgical recovery of valuable metals.