Paraffin (PW) were used as the main phase change materials,different expanded graphites (EG-300,EG-350 and EG-400) for the framework,and vanadium tailings (VT) as thermal conductivity enhancing agents.All composite phase change materials were prepared by melt-blending method,and the thermal conductivity were tested and analyzed.The results shown that the PW,adding three expanded graphite with the mass fraction of 9%,8% and 7%,had no leakage occurred.Nine VT/EG/PW were prepared by adding 1% to 3% of micron-level VT into 3 types of composite phase change materials,respectively.All VT/EG/PW material was press-molded at 4MPa,and subjected to 60 thermal cycles.Addition of VT had little effect on the thermal stability of the material.the thermal conductivity of the composite at different temperatures mostly increased,and the thermal conductivity loss rate after 60 energy storage/release cycles mostly decreased.Adding micron-level VT can enhance the composite's thermal conductivity,and slowed down the thermal conductivity decay.It shown that adding a certain amount of micron-level VT to the EG/PW composite can enhance the thermal conductivity.