Enhanced Thermal Conductivity in a Nanostructured Phase Change Composite due to Low Concentration Graphene Additives

The liquid-solid phase change enthalpy, crystallization, and thermal conductivity of graphene/1-octadecanol (stearyl alcohol) composite, a nanostructured phase change material, was investigated as a function of graphene content. The thermal conductivity (kappa) of the nanocomposite increased by nearly 2.5-fold (similar to 140% increase) upon similar to 4% (by weight) graphene addition while the drop in the heat of fusion (i.e., storage capacity) was only similar to 15.4%. The enhancement in thermal properties of 1-octadecanol obtained with the addition of graphene is markedly superior to the effect of other nanofillers such as silver nanowires and carbon nanotubes reported previously in the literature. Boosting the thermal conductivity of organic phase change materials without incurring a significant loss in the heat of fusion is one of the key issues in enabling their practical application as latent heat storage/release units for thermal management and thermal protection.