Effect of graphene aerogel on thermal behavior of phase change materials for thermal management

A phase change material consisting of three-dimensional graphene aerogel (GA) and octadecanoic acid (OA) was produced. The GA was assembled from the sheets of graphene oxide in a hydrothermal reaction. The pore sizes of the network were several micrometers and the pore walls consisted of thin layers of stacked graphene sheets. OA was impregnated into GA by capillary forces, with the GA acting as the support. The GA/OA composite had a thermal conductivity about 2.635 W/m K at a GA loading fraction of ∼20 vol%, which was about 14 times that of the OA (0.184 W/m K). The transient heating and cooling responses of the material were investigated for thermal energy storage. The GA had a low bulk density so that the weight percent of the GA in the composite was only about 15%. The composite presents a high heat storage capacity of 181.8 J/g, which was very close to the value of the OA alone (186.1 J/g).