A Better Way to Make Graphene

A new method could allow more practical manufacturing of the material.

Single-atom-thick sheets of carbon called graphene have some amazing properties: graphene is strong, highly electrically conductive, flexible, and transparent. This makes it a promising material to make flexible touch screens and superstrong structural materials. But creating these thin carbon sheets, and then building things out of them, is difficult to do outside the lab.

Now an advance in making and processing graphene in solution may make it practical to work with the material at manufacturing scale. Researchers at Rice University have made graphene solutions 10 times more concentrated than any before. They've used these solutions to make transparent, conductive sheets similar to the electrodes on displays, and they're currently developing methods for spinning the graphene solutions to generate fibers and structural materials for airplanes and other vehicles that promise to be less expensive than today's carbon fiber.

Now an advance in making and processing graphene in solution may make it practical to work with the material at manufacturing scale. Researchers at Rice University have made graphene solutions 10 times more concentrated than any before. They've used these solutions to make transparent, conductive sheets similar to the electrodes on displays, and they're currently developing methods for spinning the graphene solutions to generate fibers and structural materials for airplanes and other vehicles that promise to be less expensive than today's carbon fiber.

Most methods for making graphene start with graphite and involve flaking off atom-thin sheets of graphene, usually using chemical means. "The key is to make single-layer graphene, to not destroy it in the process, and to do it in high volume," says Yang Yang, professor of materials science and engineering at the University of California, Los Angeles. Some of the existing methods for making graphene from graphite and then manipulating it in solution involve adding soluble groups to the surface of the molecule, but this chemical change destroys graphene's electrical properties.

The Rice researchers make graphene solutions using a method they initially developed for working with carbon nanotubes. About five years ago, researchers led by the late Nobel laureate Richard Smalley discovered that highly concentrated sulfuric acid, so strong it's called a "superacid," can bring carbon nanotubes into solution by coating their surfaces with ions. Last year, the Rice group, now led by chemist Matteo Pasquali, showed they could use superacid solutions of carbon nanotubes to make fibers hundreds of meters long; the group has contracted with a major chemical company to commercialize the process.