Lauric acid/modified sepiolite composite as a form-stable phase change material for thermal energy storage

A series of novel composite phase change materials (PCMs) were prepared by impregnating lauric acid (LA) into the chemically modified sepiolite (SEP) via a vacuum impregnation method. Modification strategy was developed to improve the adsorption capacity of SEP, and the effects of thermal and chemical modification on the physical and chemical properties of SEP were investigated. The loading of LA inside the acid treated SEP could reach up to 60 wt%, which was 50% higher than that of pristine SEP. The corresponding latent heats of the composite PCMs exhibited 125.2 J/g at the melting temperatures of 42.5 degrees C and 113.9 J/g at the freezing temperatures of 41.3 degrees C, respectively. The increased latent heat could be attributed to the better microstructure of the modified SEP. The thermal conductivity (0.59 W/(m.k)) of the composite PCMs was higher than that of LA. The composite PCMs presented chemical and thermal reliability after 200 thermal cycling tests. The form-stable composite PCMs could be the promising candidate material for thermal energy storage.