Preparation and performance improvement of phase change materials with Skin-Flesh structure inspired by loofah

Abstract

Leakage and low thermal conductivity limit the application of molten salts in thermal energy storage (TES) systems. Inspired by the skin-flesh structure of loofah, a porous ceramic with dense skin was designed and prepared. The dense skin prevents molten salt leakage, and the porous ceramic enhances its thermal conductivity. The organic foam impregnation method was used to prepare the porous ceramic, and a layer of SiC slurry was coated on the surface of the porous ceramic. The resulting construct was sintered to form a skin-flesh porous ceramic (SFPC). Solar salt was then directly injected into the SFPC to create a skin-flesh composite phase change material (SF-CPCM). The results showed that leakage of molten salt was prevented when the SiC particle size in the skin slurry was less than 6 μm. The SF-CPCM demonstrated a thermal conductivity of 2.39 W/m∙K, with a porous ceramic porosity of 80%. The SF-CPCM exhibits the best heat transfer performance performance among the four forms of molten salt encapsulation. After 500 thermal cycles, the shape and thermal performance of the SF-CPCM remained stable. The skin-flesh structure proposes a new strategy for the development of TES materials.