Kinetics study of thermal decomposition of spent lithium-ion batteries

The pyrometallurgical recycling method for spent lithium-ion batteries offers several significant benefits, including industrial scalability and higher efficiency compared to other methods. However, the practical implementation would require extensive studies. This study presented the kinetics of the thermal decomposition of two types of black mass samples. Sample 1 consists mainly of cathode and anode active materials, whereas sample 2 also contains current collectors and organic materials. Two iso-conversional methods, the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, were employed to determine the activation energies. Several characterization techniques, such as Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Mass Spectrometry (MS), and Fourier Transform Infrared Spectroscopy (FTIR), were utilized to investigate the thermal decomposition behavior of the studied samples. The activation energies were calculated as 280 kJ/mol and 313.84 kJ/mol for samples 1 and 2, respectively. The heating rates do not alter the phases for example, C, Co, NiO, Co 3 O 4 MnO 2 , and Li 2 CO 3 as observed in the XRD pattern. However, the intensity of the MS curves increases for most evolved gases as the heating rate increases. FTIR spectra indicate the release of CO 2 , CO, and traces of H 2 O for sample 1. Additionally, some organic substances were released from sample 2. The results revealed that cathodic decomposition occurs around 600 °C, and metallic oxides such as NiO, Co 3 O 4 , and MnO 2 form. Further increasing the temperature would enhance the formation of CoO and MnO, as well as Ni, Co, and Mn. Meanwhile, the presence of fluorine complicates lithium recovery.