Highly compressible graphene aerogel with high thermal conductivity along both in-plane and through-plane directions

Abstract

Graphene-based thermal interface materials (TIMs), such as horizontal graphene papers and vertical graphene monoliths, commonly possess high thermal conductivity (TC) only along either in-plane or through-plane direction due to their high anisotropy structure. Three-dimensional (3D) graphene monoliths with interconnected network can extend the excellent thermal transport performances of two-dimensional graphene to macro monoliths along multi-directions. However, the high porosity of 3D graphene monoliths usually leads to low TC. Here, highly compressible graphene aerogels (HCGAs) with closely packed cell walls and regularly cellular structure were prepared. The HCGAs can be highly compressed (95% compressive strain) to reduce the porosity while maintaining the continuously thermal transport paths. Significantly increased TC along both in-plane and through-plane directions can be obtained by directly mechanical compression of the aerogels. HCGAs with initial density of 11.5 mg cm−3 at 95% compressive strain possess in-plane TC of 167.2 W m−1K−1 and through-plane TC of 46.8 W m−1K−1, which outperforms other carbon-based TIMs reported previously.