Theoretical prediction and experiment study on the thermo-physical properties of ternary carbonate for energy storage

Abstract

This study calculated the optimal formula (sample A) of ternary carbonate based melting salt using a phase diagram firstly and other four sets of ternary carbonates with different ratios were prepared by changing the content of sodium carbonate and lithium carbonate. The results showed that sample A had better comprehensive thermophysical properties, the melting point, phase change enthalpy, upper limit temperature of thermal stability and stability were the optimal. Whose melting point and phase change enthalpy were 395.57 °C and 322.06 J/g, respectively. The specific heat capacity in the solid phase (330–380 °C) enhanced slightly from 1.38 J/(g·K) to 1.84 J/(g·K) with the increase of temperature, while in the liquid phase, the specific heat capacity was maintained at 1.5 J/(g·K). The ternary carbonate only underwent simple physical mixing without chemical reactions, the decomposition temperature and thermal conductivity of sample A were 885.73 °C and 1.325 W/(m·K), respectively. The ternary carbonates exhibited good thermal stability when continuously heating and heating-cooling cycles.