Graphene has been touted as the ultimate supermaterial – better conductivity, one-atom thickness, stronger-than-steel mechanical performance etc. However, Rice scientists have discovered recently that graphene may not be so mechanically potent, after all.
Graphene is made of a single sheet of carbon atoms in a hexagonal pattern. At the very edge of the sheets, where the one-atom layer stops, the hexagonal structure is interrupted and five- or seven-atom rings form.
On the other hand, it’s been known for several years that you can’t create the perfect graphene. The so-called “perfect” hexagonal arrays are actually “enriched” with islands of graphene (grains). Boris Yakobson, a researcher at Rice, said to Material Views:
“The details are complicated but, basically… the force is concentrated there, and that’s where it starts breaking. Force on these junctions starts the cracks, and they propagate like cracks in a windshield. In metals, cracks stop eventually because they become blunt as they propagate. But in brittle materials, that doesn’t happen. And graphene is a brittle material, so a crack might go a really long way.”
This leads to real-world graphene having only half of the predicted strength. This, however, does not impede other scientists to make supercapacitors or better battery anodes from graphene. The future for this material is still bright, only not that bright as it was recently thought.