Solubility of CO2 in Molten Li2O–LiCl System: A Raman Spectroscopy Study

The molten Li2O–LiCl system is an important molten salt for CO2 capture and electrochemical transformation. In this study, the solubility of CO2 in Li2O–LiCl with 4–8 wt % concentration of Li2O was studied by Raman spectroscopy using Li2SO4 as the external standard at 873–973 K and under 101.3 kPa of CO2. Results showed that the solubility of CO2 increased with Li2O concentration and reached the maximum value of 0.1105 gCO2/gmelt at 923 K and 8 wt % Li2O. Moreover, the conversion rate of Li2O to Li2CO3 reached 94.19%. The Gibbs free energy of the reaction for Li2O with CO2 to generate Li2CO3 in the Li2O–LiCl melts was determined. The reaction was found to be spontaneous and more likely to occur with increased Li2O concentration.