Multiscale design of nanofibrous carbon aerogels: Synthesis, properties and comparisons with other low-density carbon materials

By leveraging decades of research on the catalytic synthesis of carbon nanofibers and combining it with unique processing methodology, low density monolithic carbon can be created. The process is simple, scalable and controllable. Analysis of deposition kinetics reveals that the final density of centimeter-scale carbon monoliths can be determined through basic process parameters, and the synthesis can be performed with a single step in as little as 1 h. In general, this material can be created over a large range of density (20–700 mg/cc), possesses high surface area (∼215 m2/g), is comprised of a mixture of straight and twisted carbon nanofibers (∼150–500 nm in diameter) with low crystallinity, which results in low electrical conductivity (1.32–2.83 S/m) and low thermal conductivity (∼0.03 W/mK), even at the highest densities. The materials are mechanically robust, with density-dependent elasticity values of 60–600 kPa. The methods and properties are discussed in context with other low-density carbon materials. The principal advantages of the process used in this work include the simplicity, direct control of density, and most notably, the ability to create this material with specific bulk geometry.