Abstract: Three series of molten salt composites were prepared by adding the different contents of graphene oxide（GO）， sodium graphene（Na-GO），and potassium graphene（K-GO） into the molten salts comprised with potassium nitrate（KNO3）， sodium nitrate（NaNO3），and lithium nitrate（LiNO3） via physical blending.The influences of the functionalizing graphene content，oxidation，sodium-and-potassium treatment of graphene on the melting point，thermal decomposition temperature， thermal conductivity，and viscosity of molten salt composites were investigated.When the functionalizing graphene content was at 0.1%~5%，the melting point of molten salt composites decreased，then changed slightly with the increase of the functionalizing graphene content.Meanwhile，the addition of Na-GO decreased the melting point of molten salt composites more than that of GO and K-GO.Moreover，the thermal decomposition temperature of molten salt composites increased with the increase of the functionalizing graphene content.The addition of GO，Na-GO，and K-GO increased the thermal conductivity and reduced the mobility of molten salt composites.The molten salt composites filled with 0.5%~1% of Na-GO had favorable comprehensive performance based on the above analysis.

Key words: molten salts, functionalizing graphene, composites, melting point, thermal decomposition temperature