World record: Scientists produce the lightest material in the world

18th July 2012

A network of porous carbon tubes that is three-dimensionally interwoven at nano and micro level – this is the lightest material in the world. It weights only 0.2 milligrams per cubic centimetre, and is therefore 75 times lighter than Styrofoam, yet it is very strong nevertheless. Scientists at Kiel University (KU) and Hamburg University of Technology (TUHH) have named their joint creation "Aerographite". The results are published as the cover story in Advanced Materials and were presented yesterday to the public.

Aerographite is jet-black, stable, electrically conductive, and ductile. With these unique properties and its very low density, the carbon-made material clearly outperforms all similar materials.

"Our work is causing great discussions in the scientific community. Aerographite weighs four times less than the previous world record holder", says Matthias Mecklenburg, co-author and Ph.D. student at the TUHH. The previous lightest material, a nickel material that was presented to the public about six months ago, is also constructed of tiny tubes. Only, nickel has a higher atomic mass than carbon. "Also, we are able to produce tubes with porous walls. That makes them extremely light", adds Arnim Schuchard, co-author and Ph.D. student at Kiel University.

Despite its low weight, Aerographite is highly resilient. While lightweight materials normally withstand compression but not tension, Aerographite features both: an excellent compression and tension load. It is able to be compressed up to 95 percent and be pulled back to its original form without any damage, says professor Rainer Adelung of Kiel University. "Up to a certain point, the Aerographite will become even more solid and therefore stronger than before", he points out. Other materials become weaker and less stable when exposed to such stress. "Also, the new material absorbs light rays almost completely. One could say it creates the blackest black", acknowledges Hamburg’s Professor Karl Schulte.

Due to its unique material characteristics, Aerographite could fit onto the electrodes of lithium-ion batteries. In that case, only a minimal amount of battery electrolyte would be necessary, leading to a reduction in the battery’s weight. This purpose was outlined by the authors in a recently published article. Areas of application for these small batteries might be electric cars or e-bikes. Thus, the material would contribute to the development of greener transport.

According to the scientists, further areas of application could be the electrical conductivity of synthetic materials. Non-conductive plastic could be transformed, without causing it to gain weight. Components for aviation and satellites would benefit, since these vehicles have to endure very high amounts of vibration. The material could be a promising aid in water purification. It might act as an adsorbent for persistent water pollutants, as it could oxidise or decompose and remove these.