Strange 'Carbon Foam' is World's Lightest Material
Aerographite is now the world
What material is 75 times lighter than Styrofoam and could one day be used to reduce the weight of rechargeable car batteries?
It's "Aerographite," now the lightest material in the world.
The new material is made of an airy mesh of tiny carbon tubes, resembling a super-porous version of the graphite in school pencils. Researchers, in a paper published in the July 10 issue of the journal Advanced Materials, also called it a "foam-like carbon structure."
Aerographite has a density of about 0.2 milligrams per cubic centimeter, beating out NASA's aerogels, with a density of 1 milligram per cubic centimeter, as well as the last record-holder, a nickel-based material with a density of 0.9 milligrams per cubic centimeter.
A team of scientists from the Hamburg University of Technology and the University of Kiel, both in Germany, created the carbon foam by first making a porous mold out of zinc oxide. They streamed carbon-rich gas over the mold, coating the mold with tiny layers of carbon only a few atoms thick. Afterward, they streamed in hydrogen, which turns the solid zinc oxide into a gas, leaving behind only the carbon structure.
"Think of the Aerographite as an ivy web, which winds itself around a tree. And then take away the tree," Rainer Adelung, a materials scientist at the University of Kiel and one of Aerographite's creators, explained in a statement.
The new carbon foam has several interesting characteristics: It conducts electricity and it strongly repels water. Although aerogels appear slightly translucent, Aerographite absorbs light and looks opaque and black.
It's also strong and flexible for its density. It can spring back to its original size after getting compressed 95 percent and it can bear 35 times more force than aerogels.
Aerographite could go in the electrodes in super-capacitors or in rechargeable lithium-ion batteries for electric cars, Adelung and his colleagues wrote in the paper. A car battery with an Aerographite electrode would need less electrolyte than current batteries, so it would be lighter overall, according to the Hamburg University of Technology.
For other uses, it's easy to tweak Aerographite's microscopic structure, giving it slightly different properties for different needs, the carbon foam's creators say. "The great thing is that we are able to affect the characteristics of the Aerographite," said Arnim Schuchardt, another University of Kiel materials scientist who worked on the ultra-light material. "There is considerable scope."