Facile preparation of carbon nanotube aerogels with controlled hierarchical microstructures and versatile performance

Carbon nanotube (CNT) aerogels with controlled hierarchical microstructures and versatile performance were prepared by a freeze-drying method under the facile freezing temperature of −20 °C. The as-prepared CNT aerogels were composed of CNT/binder (sodium carboxymethylcellulose, CMC) hybrid sheet structures, whose morphologies could be controlled by changing the weight ratio of CMC solution to CNT paste. The aerogels displayed a very low density of 32.7–77.7 mg/cm3, fairly high mechanical strength, good machinability, an outstanding electrical conductivity of 0.034–0.162 S/cm, and an ultralow thermal diffusivity of 2.09–4.54 mm2/s. In addition, we proposed formulas to describe the relationships between volume density of the fabricated aerogels and solid content or carbon content in CNT slurries.