Kinetic Evaluation of In-Situ Carbothermic Processing of Mixed Electrode Material of Discarded Li-Ion Batteries

Abstract

Recycling of spent lithium-ion batteries (LIBs) for metal recovery is inevitable because of environmental and resource conservation considerations. Evaluation of the kinetics parameters is crucial for understanding the thermal response of mixed electrode material for the development of the thermal recycling process. In this study, thermal treatment of mixed electrode (anode and cathode) material resulted in an in-situ indigenous carbothermal reduction of cathode material. The thermal response of mixed electrode material was investigated at different heating rates under argon and air atmosphere. Kinetic parameters, such as the activation energy and pre-exponential factor, were evaluated using other kinetic methods. The average activation energy for the thermal dissociation of mixed electrode material under the air atmosphere is estimated as ~ 180 kJ/mol. The activation energy using different kinetic models was calculated. The product layer diffusion model was found to fit with the activation energy of 52.1, 121.4, 125.3, and 71 kJ/mol for Co, Mn, Ni, and Li recovery, respectively. The optimum product of in-situ carbothermic reduction of mixed electrode material at 900 °C, 60 minutes comprises Co, MnO, and Ni (Co: 61.6 pct, Mn: 17.8 pct, Ni: 7.1 pct, O: 13.5 pct) with a saturation magnetization of 102 emu/g.