Fundamental thermokinetic study of a sustainable lithium-ion battery pyrometallurgical recycling process

With increased global consumption of Lithium-ion batteries (LIBs), a sustainable recycling process is necessary to reduce wastes and retrieve highly-valued elements. But to achieve an optimized sustainable recycling process, a fundamental understanding of the thermokinetic reactions during pyrometallurgical LIB recycling is essential. In this work, the thermodynamics and kinetics of high-temperature reactions for LIBs during pyrometallurgical recycling are studied using a thermo-gravimetric analyzer (TGA) equipped with a gas mass spectrometer. Cylindrical composite pellets comprised of cathode and anode active materials were heated from room temperature (RT) to 1500 °C at a constant heating rate of 20 °C/min. By comparing the measurements of the mass loss and simultaneous gas evolution, the anticipated theoretical thermodynamic reactions are confirmed and determined, which is fundamental to the development of a sustainable pyrometallurgical process to recover valuable metals in LIBs. Isothermal reductions from 850 to 1000 °C indicated reactions to be temperature sensitive and mass transfer to be comparatively fast. Using various kinetics models, the uniform internal reduction mechanism was found to be dominant.