What is Graphene?

Graphene is an atom-thick layer of carbon atoms arranged in a hexagonal lattice. It's a component of graphite (among other things, used in pencil tips), but graphene itself is a remarkable substance - with many surprising properties that have repeatedly earned it the "wonder material" title.
Graphene has many extraordinary properties. It is about 100-300 times stronger than steel and has a tensile stiffness of about 1020 GPa. It is the best thermal conductor at room temperature (thermal conductivity ~5300 W·m−1·K−1) and the best known electrical conductor (studies show electron mobility in excess of 15,000 cm2·V−1·s −1) and it is optically transparent (with light absorption at πα ≈ 2.3% white light or 97.7% transmittance).

Because it is less than one atom thick (0.33 nm) or about a million times thinner than a sheet of paper, it is a very light material weighing about 0.77 mg/m2 and has an extremely high surface area (theoretical specific surface area is 2630 m2/G).