Green and Energy-Saving Recycling of LiCoO2 by Synergetic Pyrolysis with Polyvinyl Chloride Plastics

Finding green and profitable recovery methods has always been a great challenge for Li/Co recovery from LiCoO2 (LCO) in waste lithium-ion batteries (LIBs). A top priority was specially proposed on energy and material consumptions for the industrialization of carbothermal technology from an economic point of view. Meanwhile, pollution caused by plastic wastes including polyvinyl chloride (PVC) plastics has already become a serious environmental issue. Therefore, in this study, we proposed a PVC–LCO synergetic pyrolysis strategy for Li/Co recovery. Results showed that the LiCoO2 was fully destructed to Li2CO3, CoO, Co, and Cl-containing salts at 450 °C for 90 min with a PVC/LCO mass ratio of 1:1. The reaction temperature was decreased significantly in comparison to the ever-reported values of the carbothermal technology. High-purity Li and Co were then separated simply by water leaching, with a recovery rate of 92.50 and 94.85%, respectively. Simultaneous thermogravimetric–mass analysis, thermodynamic analysis, and density functional theory revealed the reaction mechanisms as three-stage PVC cracking together with Li/Co–Cl bond formation after Cl adsorption on surface Li/Co of LCO. Overall, the PVC synergetic pyrolysis strategy possessed distinct advantages owing to the remarkable energy-conserving and chemical-free features and provided an economical, green, and scalable solution for LIB recycle.