Preparation and performance of paraffin/alkali modified diatomite/expanded graphite composite phase change thermal storage material

Through alkali treatment, the pore structure of diatomite (DIA) was optimized, the porosity was increased, and the paraffin loading was increased. A novel paraffin/alkali-modified DIA/expanded graphite (EG-alDIAP) composite with stable properties was prepared by direct impregnation method. The relationship between structure and properties of the material was studied. The results showed that the paraffin loading of the composite phase change material increased from 47.4% to 61.1%, thereby improving the heat storage performance of the composite material. The addition of expanded graphite (EG) to the modified diatomite improved the heat transfer capacity of the composite material. The addition of mass fraction of 10% EG increased the thermal conductivity by 113% (from 0.276 to 0.589 W center dot m-1 center dot K-1). With the increase of EG content, the latent heat of the composite phase change material increased slightly, but the chemical compatibility and stability did not change significantly. The paraffin/alkalimodified DIA composite containing 10% expanded graphite had reliable energy storage, good temperature regulation performance and heat storage and release capacity.