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 degrees 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. (C) 2020 Elsevier B.V. All rights reserved.