Synthesis and characterization of thermochemical storage material combining porous zeolite and inorganic salts

Thermal energy storage has the potential to decarbonize the heating sector, facilitating the use of renewable energy sources, in particular solar thermal energy. In this paper we present a study on thermochemical storage material composed of inorganic salts hosted in the porous matrix of zeolite 13X; we prepared a series of composites containing different amounts of inorganic salts – MgCl₂, MgSO₄ by impregnation method and we characterized them by multiple experimental techniques: energy storage and adsorption/desorption rates were assessed using simultaneous thermal analysis by coupling thermogravimetric and differential scanning calorimetry, microstructure, and composition were assessed through scanning electron microscopy and energy-dispersive X-ray spectroscopy. Finally, thermal conductivity was measured by laser flash analysis. With our composite material, we achieved an energy density of 400 kJ/kg across the temperature range 30–150°C and a 35% increase in thermal conductivity by adding 1% of multiwall carbon nanotubes. These features make the material an interesting option for thermal storage in buildings. We attribute the behavior of the material to the combination of large zeolite-specific area coupled with the heat of water sorption/hydration of MgCl₂, MgSO₄.