Effect of nano-SiC on thermal properties of expanded graphite/1-octadecanol composite materials for thermal energy storage

In this study, a series of 1-octadecanol (OD) composite phase change materials (PCMs) with stable shape were prepared by adding nano‑silicon carbide (SiC), expanded graphite (EG) and SiC/EG composite respectively. The thermal conductivity of OD/SiC, OD/EG and OD/SiC/EG were 0.432, 0.607 and 0.996 W·m −1 ·K −1 respectively when the mass fraction was all 5 wt%. The results indicated that among the above three additives, SiC/EG composite had the best enhancement effect on the thermal conductivity of organic PCMs, while the thermal conductivity of OD/SiC/EG composite with 9 wt% SiC/EG addition was 1.674 W·m −1 ·K −1 , which was more than 4 times that of pure OD. SEM results showed that SiC distributed uniformly on the surface of EG without obvious agglomeration. SiC/EG could replace EG as a new excellent thermal conductivity reinforcement. The phase transition temperature and phase transition enthalpy of OD/SiC/EG composite were 58.6 °C and 210 J/g, respectively, which also processed sufficient thermal stability. The prepared OD/SiC/EG composite heat storage materials had both high thermal conductivity and large storage energy density , which can meet the demands of low temperature heat storage fields, such as thermal control of electronic components, building materials and solar energy systems.