Carbon Aerogel with High Thermal Conductivity Enabled by Shrinkage Control

Carbon aerogels are often applied to construct a continuous pathway in composites for thermal conductivity enhancement. However, the properties exhibited by carbon foams, such as low density and high porosity, reduce the filler loading in composites, limiting the resulting thermal conductivity. Methods to improve filler loading in composites, such as hot pressing and compressing, delivered by recent studies lead to orientation change or architecture distortion. It remains a great challenge to construct carbon aerogels with a compact skeleton applying to thermal interface materials in an industrially available and economically friendly manner. We here put forward an in situ assembled and post-degas strategy to shrink expanded graphite aerogels. The degassed-expanded graphite (D-EG) aerogels with a densified structure hold a more compact pathway for phonon/electron transfer. D-EG impregnated with polydimethylsiloxane exhibits a thermal conductivity of 9.92 W m-1 K-1 at a mass content of 11.83 wt %. This simple strategy focuses on enhancing the density of the thermal transport pathway while maintaining the orientation of graphite and demonstrates a viable way to optimize the thermal conductivity of carbon foam composites.

Automated summary

Carbon aerogels are commonly used in composites to enhance thermal conductivity, but their low density and high porosity limit the amount of filler loading. Constructing carbon aerogels with a compact skeleton remains a challenge. This study proposes an in situ assembled and post-degas strategy to shrink expanded graphite aerogels, resulting in a densified structure that improves phonon/electron transfer and increases thermal conductivity in composites.