Chlorination mechanism and kinetics of cathode materials for spent LiCoO2 batteries in the presence of graphite

Abstract

In the face of the rapid growth of lithium industry's demand for energy metals, recycling spent lithium-ion batteries (LIBs) has become the key to the sustainable development of related industries. The chlorination roasting process is effective at recycling spent LIBs. Factories usually recycle the black mass as raw material instead of only the cathode material in actual production. The black mass is mainly composed of cathode material and graphite. However, studies on the effect of graphite on the chlorination process of cathode materials are lacking. In this study, the effect of graphite on the chlorination process of cathode materials is investigated, focusing on the reaction mechanism and kinetics aspects. The results show that the presence of graphite can accelerate the destruction of the LiCoO2 structure, thereby reducing the pyrolysis temperature of LiCoO2. The cobalt in the roasted product exists in the form of metallic cobalt rather than cobalt oxide or cobalt chloride. The reaction model of the LiCoO2 chlorination stage conforms to the random nucleation and nuclear growth modes. The mechanism function is g(α) = [-ln(1-α)]3/4. Ea and A are 196.107 kJ/mol and 3.575 × 106, respectively. Furthermore, thermodynamic activation parameters are calculated and equations are established.