Preparation and properties of a low condensation point molten salt LiNO₃-KNO₃-NaCl

LiNO 3 -KNO 3 binary salt is often chosen as a thermal storage material due to its advantages, including low cost, low viscosity, and weak corrosiveness. However, the relatively high melting temperature, low thermal conductivity, and low enthalpy of phase transition limit its application. This paper employs a static mixed melting method to prepare a 40% LiNO 3 -60% KNO 3 (LK) binary nitrate, and on this basis, utilizes NaCl as a modified salt to prepare LK-NaCl (LKN) ternary molten salt. We explore the effect of NaCl (1 wt% -15 wt%) on the performance of LKN. LK and LKN were characterized by using DSC, XRD, TG, Hotdisk thermal constant analyzer, etc. The results indicated that the melting point of LKN with 4 wt% NaCl is 112.1°C, the enthalpy of melting is 189.2 J/g, and the condensation point is 91.4°C. Compared to LK salt, the melting temperature decreases by 24.4°C, the melting enthalpy increases by 18.4 J/g, and the condensation point decreases by 23.2°C. The thermal conductivity of LKN is 0.4248 W·m −1 ·K −1 higher than that of LK salt. The decomposition temperature of LKN is 582°C, which is 13°C higher than that of LK. LNK has good heat storage capacity, high-temperature stability, and enormous application potential.