Nucleation–Oxidation coupled technology for High-Nickel ternary cathode recycling of spent Lithium-ion batteries

Leaching kinetics of fluorine during the aluminum removal from spent Li-ion battery cathode materials

The high content of aluminum (Al) impurity in the recycled cathode powder seriously affects the extraction efficiency of Nickel, Cobalt, Manganese, and Lithium resources and the actual commercial value of recycled materials, so Al removal is crucially important to conform to the industrial standard of spent Li-ion battery cathode materials. In this work, we systematically investigated the leaching process and optimum conditions associated with Al removal from the cathode powder materials collected in a wet cathode-powder peeling and recycling production line of spent Li-ion batteries (LIBs). Moreover, we specifically studied the leaching of fluorine (F) synergistically happened along with the removal process of Al, which was not concerned about in other studies, but one of the key factors affecting pollution prevention in the recovery process. The mechanism of the whole process including the leaching of Al and F from the cathode powder was indicated by using NMR, FTIR, and XPS, and a defluoridation process was preliminarily investigated in this study. The leaching kinetics of Al could be successfully described by the shrinking core model, controlled by the diffusion process and the activation energy was 11.14 kJ/mol. While, the leaching of F was attributed to the dissolution of LiPF6 and decomposition of PVDF, and the kinetics associated was described by Avrami model. The interaction of Al and F is advantageous to realize the defluoridation to some degree. It is expected that our investigation will provide theoretical support for the large-scale recycling of spent LIBs.

Selective lithium extraction from spent lithium-ion batteries through polyvinyl chloride thermal decomposition-based gas-solid reaction

The recovery of valuable metals from waste battery materials and the thermal decomposition of PVC both require significant energy and material consumption. In this study, we propose an innovative strategy that integrates the lithium extraction process from spent LiNi0.85Co0.15Al0.05O2 (S-NCA) with PVC pyrolysis, resulting in a substantial reduction in energy consumption and chemical additive. Various characterization techniques, including SEM, TEM, XRD, and XPS, are employed to investigate the mechanism of gas-solid lithium extraction and provide valuable insights into the migration pathway of lithium from S-NCA to soluble LiCl. The optimal conditions for the process were determined as follows: a temperature of 600 °C, S-NCA/PVC mass ratio of 1:4, and a baking time of 2 h, achieving a lithium extraction efficiency of 94.37 %. The research provides valuable insights for the valorization of PVC thermal decomposition and lithium extraction from NCA, presenting a novel approach for future applications.