When you consider “foam,” it’s usually not for its incredible strength. But when graphene is involved, all the rules change. That’s certainly true of a newly developed graphene foam, developed at Rice University’s Department of Chemistry, anyway.
For those unaware, graphene is an allotrope of carbon that, at one-atom thick and weighing just .77 mg, is 100 – 300 stronger than steel. It’s an incredibly strong, lightweight, durable and conductive material that may have huge implications for consumer electronics.
At Rice University, chemists created a highly-conductive chunk of graphene foam called “rebar graphene.” According to chemist James Tour, “We developed graphene foam, but it wasn’t tough enough for the kind of applications we had in mind, so using carbon nanotubes to reinforce it was a natural next step.”
With carbon nanotubes as reinforcement, the researchers’ graphene foam could support 3,000 times its own weight, as opposed to just 150 without the nanotubes.
How was the foam created? Powdered nickel catalyst, surfactant-wrapped multiwall nanotubes, and sugar as a carbon source were combined to create 3D structures. The nanotubes then began to unzip and bond with the graphene, lending it extra strength.
When the materials mixed and water evaporated, the resulting pellets were “pressed into a steel die and then heated in a chemical vapor deposition furnace, which turned the available carbon into graphene.” After being processed again to move remnants of nickel, it came out in a screw-shape. According to Tour, the method can be scaled up simply.
You might wonder what the purpose of superstrong graphene foam is, and it’s a great question. The researchers’ foam was tested as an electrode in lithium-ion capacitors, and was determined to be mechanically and chemically stable. Larger-scale foam could be molded into any shape and used to create flexible batteries, act as a supportive material, or be used to sense chemicals in potentially toxic environments.