Fundamentals of the temperature-dependent electrical conductivity of a 3D carbon foam-Aerographite

Aerographite is a 3D interconnected carbon foam with a hollow tetrapodal morphology. The properties of Aerographite, especially the electrical conductivity, are strongly dependent on the wall thickness, the degree of graphitization and the ambient temperature. The tailored-carbon-structures like wall thickness (number of layer) and state of graphitization determine the electrical properties of the carbon foam. The wall thickness of Aerographite can be controlled by a stepwise reduction of solid arms of sacrificial template with respect to synthesis time, in which wall thicknesses between 3 and 22 nm can be easily achieved. The decreasing of the wall thickness leads to a reduced electrical conductivity of untreated Aerographite. Contrary, the conductivity of annealed Aerographite increased with reducing of the wall thicknesses. The morphology of Aerographite has been analyzed via scanning electron (SEM), transmission electron (TEM) microscopy and Raman spectroscopy. Furthermore, the dependency of the electrical conductivity on the temperature is measured and based on this the band gap energy is calculated. As a result, Aerographite shows a metallic conductive behaviour which can be changed semiconducting nature by further high temperature treatment.