Thermodynamic study on the dissolution of lithium cobaltate in the cathode of spent lithium-ion batteries recovered from supercritical water

Abstract

The recovery of cathode metal materials in lithium-ion batteries using supercritical water (SCW) has attracted more and more attention. To explore the separation and extraction method of LiCoO2 using SCW, the thermodynamic experiments of LiCoO2 dissolution in SCW were carried out in this paper to study the effect of essential parameters on the solubility of LiCoO2 in SCW. The results show that the solubility decreases with an increase in temperature and increases with an increase in pressure and density. The molecular dynamics were applied to simulate the dissolution process of LiCoO2 and provide a theoretical explanation for the experimental law. The solubility of LiCoO2 in SCW was also calculated using the R-HKF equation of state, and high-precision prediction results were verified using experimental data. This work will provide a reference for obtaining the solubility of cathode metal compounds of spent lithium-ion batteries in the supercritical state.