Toward highly thermally conductive all-carbon composites: Structure control

All-carbon composites are ideal heat-dissipating materials because they possess a high thermal conductivity (K), excellent mechanical properties, high temperature resistance, low coefficient of thermal expansion, outstanding chemical stability, and so on. The rapid development of science and technology has put forward the need for a higher K of all-carbon composites. Different from individual carbon materials, all-carbon composites have assembled structures, including the interface, orientation, and pores, which provide challenges and opportunities to improve the thermal and mechanical properties. Until now, a number of studies have reported on how to adjust the K of various all-carbon composites by controlling their microstructures and mesostructures. This review compiles recent research progress on highly thermally conductive all-carbon composites, including flexible carbon papers (carbon nanotube paper, graphene paper, exfoliated graphite paper), stiff carbon blocks (graphite block, carbon fiber block), and porous carbon foams (pitch-based carbon foam, graphene-based carbon foam, three dimensional graphene-carbon nanotube-based carbon foam). The key structures and their control methods related to their high K are outlined. Finally, the strategies and challenges in the development of highly thermally conductive all-carbon composites are presented.