Tailoring anisotropic thermal properties of reduced graphene oxide/multi-walled carbon nanotube hybrid composite films

In this study, reduced graphene oxide/multi-walled carbon nanotubes (rGO/CNT) hybrid films were successfully fabricated by vacuum filtration followed by the hydrothermal reduction process. Thermal conductivities in in-plane and through-plane directions of the hybrid films with different CNT loadings are systematically investigated using the laser flash method. Study on the anisotropy of both structural and heat-conductive properties of the hybrid film with 5 wt.% CNT loading, which has been subjected to a hot-press process, reveals a remarkable improvement in in-plane thermal conductivity, from 787.25 W/m·K to 836.80 W/m·K. Moreover, both in-plane and through-plane thermal conductivities of the hybrid film are found to increase with temperature, up to 1224.58 W/m·K at 85 °C for in-plane conductivity. With features of good flexibility, high thermal conductivity, and considerable anisotropic thermal property, the hybrid rGO/CNT films therefore show great potentials for heat management applications.