Investigation on thermal conductivities of pentaerythritol-graphene composites for thermal energy storage

Abstract

Low thermal conductivity is one of the major disadvantages that limit the practical application of energy storage materials. In this paper, the thermal physical properties and thermal conductivity of the composite phase change materials, in which the pentaerythritol is used as the matrix material and graphene/alumina as the thermal conductive fillers, is respectively investigated with experimental research and simulation analysis. The DSC results show that the specific heat capacity (25 °C) of the composite is improved because of the graphene. Additionally, the addition of graphene makes the phase change temperature and latent heat value of phase change slightly increase. As the mass percentages of thermal conductive filler increases, the thermal conductivity of pentaerythritol-graphene(PE-GE) as well as pentaerythritol-alumina(PE-Al2O3) composite increases gradually, but graphene has a more excellent effect. With increasing the mass fractions of graphene, the changing trend of interfacial thermal conductivity is consistent with the overall thermal conductivity because of that the interfacial thermal conductivity characterizes the combination of thermally conductive fillers and matrix materials, and the local promotion will affect the whole. Furthermore, the graphene structure changes towards better combination and more uniform dispersion with pentaerythritol as the increase of carbon atom spacing in graphene. In addition, the promoted overall thermal conductivity of the composite benefits from the structural change of the thermal conductive filler.