Thermal and electrical properties of graphene/carbon nanotube aerogels

Graphene and carbon nanotube (CNT) aerogels provide combinations of mechanical, thermal, and electrical properties that are interesting for a variety of applications. In this work, the impact of three different reducing agents (l-ascorbic acid (LAA), HI and NaHSO3) and carbon nanotubes on the morphologies and properties of the graphene aerogels (GAs) are studied systematically. Additional, the impact of thermal annealing at 450 °C for 5 h under Ar environment is also investigated. Annealing treatment and the addition CNTs enhance the electrical conductivities of the GAs up to a factor of 5. Thermal annealing impacts the surface area of the GAs. Specifically, the surface areas of those reduced by HI and NaHSO3 decreased by 30%, while those reduced by LAA or dispersed with CNTs increased by 15%. The thermal conductivity of the highly porous GAs is measured using an improved infrared microscopy technique to be ∼0.10 W/(m K). The optimization of the nanostructures and properties of the GAs is important for various applications, such as energy storage devices and nanocomposites.