Recycling of LiCoO₂ from the cathode of a waste lithium battery via reduction in a molten salt

A new method for recycling and resynthesizing a lithium battery cathode material was developed. A LiCl-KCl molten salt was used as a medium. The raw materials were LiOH·H 2 O obtained by membrane electrolysis and Co 2 O 3 obtained by carbothermal reduction, and the high-performance cathode material LiCoO 2 was synthesized by molten salt method, and then placed into a battery for recycling. The specific reaction process and reaction kinetics for the LiCoO 2 synthesis were studied by TG-DSC thermal analyses. The effects of different reaction conditions on the structure and morphology of the LiCoO 2 were studied by XRD and SEM. The battery performance of the LiCoO 2 was characterized with electrochemical analyses. The activation energies of the three endothermic reactions occurring in the synthetic process were calculated with the Kissinger method and were 34.212 kJ·mol −1 , 168.53925 kJ·mol −1 and 221.26181 kJ·mol −1 . The experimental battery prepared from a LiCoO 2 sample calcined at 720 °C for 7 h showed first charge–discharge specific capacities of 150 mAh/g and 147 mAh/g, and the coulombic efficiency was 98%. The discharge specific capacity after 50 charge and discharge cycles was still 129 mAh/g. The battery showed good charge and discharge performance after rate cycling.