Graphene Aerogels: Structure Control, Thermal Characterization and Thermal Transport

Graphene aerogel (GA) as one of the innovative carbon nanostructured materials is superior with flexibility, strong mechanical strength, lightweight, high porosity and excellent durability, which attracted wide research interests and fulfill the requirements for various novel applications in energy conversion and storage, sensor, thermal management, and environment areas, etc. The thermal property among other important properties of GA is important for its novel applications. In this work, we first introduce the synthesis and microstructure control method for GA, including pore size control, anisotropic pore structure control, and heterostructure control. The methods for measuring the thermal conductivity of bulk GAs in air (apparent k) and the k of solid matrix of GAs are introduced in detail, respectively. Finally, we review the thermal transport models for GAs, including the air–solid coupling models, models for calculating the intrinsic thermal properties of graphene nanoflakes, as well as the thermal reffusivity model and dominating thermal contact resistance model. Challenges and opportunities in the study of thermal transport in 3D GAs are discussed. Considering the remarkable complexity of physical/chemical structure of GAs, there is still a large room in understanding fundamentals of energy transport in these three-dimensional graphene networks, which will pave the way toward their novel applications in the near future.