Porous, 3D Graphene: MIT Scientists Make ‘One Of The Strongest, Lightest Materials Known’

In its atom-thin 2D form, graphene is one of the strongest materials known to man, but scientists have struggled to translate that strength of the thin carbon sheets into useful three dimensional materials. Until now, that is.

In an announcement Friday, researchers from the Massachusetts Institute of Technology (MIT) said they had “designed one of the strongest lightweight materials known, by compressing and fusing flakes of graphene, a two-dimensional form of carbon.” One of the variants of the lightweight material has a density of just 5 percent that of steel, but is still 10 times stronger.

A study published by the MIT researchers Friday in the journal Science Advances also found that creation of the new porous, 3D form had less to do with the material itself and more to do with the unusual geometric configuration the researchers used, opening up the possibility of creating other light and strong materials using the similar geometric features.

2D materials like graphene exhibit phenomenal strength and unique electrical properties, but due to their extreme thinness, can’t be readily used in applications where those properties would prove very useful, such as the manufacture of vehicles, buildings or electronic devices.

“What we’ve done is to realize the wish of translating these 2D materials into three-dimensional structures,” Markus Buehler, leader of the research group and lead author of the study, titled “The mechanics and design of a lightweight three-dimensional graphene assembly,” said in the statement.

Using a combination of heat and pressure, the researchers, led by Buehler, compressed small flakes of graphene which produced stable structures resembling some corals and a type of microscopic algae called diatom.

“Once we created these 3D structures, we wanted to see what’s the limit — what’s the strongest possible material we can produce,” Zhao Qin, a co-author on the study, said.

The study also rules out a possibility that had been previously proposed: that it could be possible to create 3D graphene structures which would be lighter than air and would therefore make for a durable replacement for helium in balloons. The study found such a structure would have very little density and therefore collapse under the weight of surrounding air pressure.

However, the potential applications, especially that of the geometric arrangement identified in the study, are numerous. Concrete made with such porous geometry would have similar strength as usual but would weigh a fraction of what it usually does. The air spaces inside the concrete would also make it a better insulating material. Because of the tiny pores, such materials could be used in filtration systems too.

“You can replace the material itself with anything. The geometry is the dominant factor. It’s something that has the potential to transfer to many things,” Buehler said.