With a density of less than 0.2 mg/cm³, it is barely there at all. Researchers at the Hamburg University of Technology and the University of Kiel, both in Germany, made it from a network of hollow carbon tubes grown at nano and micro scales. As the electron microscope picture above shows, it is mostly empty space, though if you held a clump in your hand, it would look like a black sponge. Read more
Aerographites are ultralow density solids that resemble classical aerogels in many regards (in fact, by some definitions, aerographites are aerogels, simply produced by an unconventional process). At their essence they are frameworks with hollow struts made of graphite deposited through chemical vapour deposition onto a template that disappears as the material is made. Read more