That's pretty cool. But I'm a bit confused... FTA, the aerographite density is 0.2 mg/cm3.
From Wikipedia on Aerogel (another very lightweight solid) [1], The lowest-density aerogel is a silica nanofoam at 1 mg/cm3, which is the evacuated version of the record-aerogel of 1.9 mg/cm3. The density of air is 1.2 mg/cm3 (at 20 °C and 1 atm). Only the recently manufactured metallic microlattices have a lower density at 0.9 mg/cm3.
How are they computing the density of the aerographite such that it doesn't float away (having 1/6 the density of air)? Are they only considering the mass of the carbon and not the internal air?!