Thermophysical properties of LiF–LiCl–Li₂CO₃ eutectic mixture/multi-walled carbon nanotubes for thermal energy storage

Latent heat thermal energy storage based on solid-liquid phase change material has a huge potential in dealing with mismatch between energy demand and supply. LiF–LiCl–Li₂CO₃ ternary system was screened out for high temperature energy storage material due to its good thermophysical properties. Its eutectic composition (X_LiF = 28.41 mol%, X_LiCl = 55.09 mol% and X_Li2CO3 = 16.50 mol%) was predicted based on the developed thermodynamic model and verified experimentally. The melting point, phase change latent heat, heat capacity, thernal diffusivity, thermal conductivity and thermal stability of LiF–LiCl–Li₂CO₃ eutectic mixture were measured. And the influence of the addition of multi-walled carbon nanotubes (MWCNTs) were analyzed. It was found that adding MWCNTs could increase the latent heat, specific heat capacity, thermal diffusivity and thermal conductivity of LiF–LiCl–Li₂CO₃ eutectic mixture, while didn't significantly change the melting temperature.