Thermodynamic investigation on ion structure and conductivity of LiF–NdF 3 molten salt

This article develops seven mathematical models to investigate how NdF 3 anions coexist in LiF–NdF 3 molten salt. The influence of the LiF/NdF 3 mole ratio (CR) and temperature on the ion structure of the molten salt was thoroughly examined through thermodynamic calculations, and the conductivity and transference number of the ions in the molten salt were predicted using a model that has five complicated anions salt. LiF–NdF 3 molten salt's ion structure analysis shows that the predominant anions in the system were NdF 4 − , NdF 5 2− , NdF 6 3− , Nd 2 F 7 − , and NdF 7 4− , along with F − . The degree of ion aggregation in the molten salt system can be decreased by increasing the LiF content, improving the system's electrical conductivity. High temperature promotes the transformation of complex anions to simple anions in the molten salt, enhancing the transfer ability of simple anions, which is beneficial to improve the electrical conductivity of the molten salt. The calculated conductivity value agrees with the value that was measured. As the percentage of NdF 3 rises, the calculated value of LiF–NdF 3 molten salt conductivity falls, and the rate of decline slows. The reason for the change in conductivity was related to the ion variation.