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Graphene foam gets big and tough

Nanotube-reinforced material can be shaped, is highly conductive

Date:
February 14, 2017
Source:
Rice University
Summary:
Graphene foam reinforced with carbon nanotubes can hold thousands of times its own weight and still bounce back to its full height. The material is thermally stable and highly conductive, making it suitable for batteries and other electrical applications.
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This macroscale piece of rebar graphene was formed into a screw shape. The highly conductive foam was tested as an electrode in lithium ion capacitors and found to be mechanically and chemically stable.
Credit: Tour Group/Rice University

A chunk of conductive graphene foam reinforced by carbon nanotubes can support more than 3,000 times its own weight and easily bounce back to its original height, according to Rice University scientists.

Better yet, it can be made in just about any shape and size, they reported, demonstrating a screw-shaped piece of the highly conductive foam.

The Rice lab of chemist James Tour tested its new "rebar graphene" as a highly porous, conductive electrode in lithium ion capacitors and found it to be mechanically and chemically stable.

The research appears in the American Chemical Society journal ACS Applied Materials and Interfaces.

Carbon in the form of atom-thin graphene is among the strongest materials known and is highly conductive; multiwalled carbon nanotubes are widely used as conductive reinforcements in metals, polymers and carbon matrix composites. The Tour lab had already used nanotubes to reinforce two-dimensional sheets of graphene. Extending the concept to macroscale materials made sense, Tour said.

"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," Tour said.

The three-dimensional structures were created from a powdered nickel catalyst, surfactant-wrapped multiwall nanotubes and sugar as a carbon source. The materials were mixed and the 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 further processing to remove remnants of nickel, the result was an all-carbon foam in the shape of the die, in this case a screw. Tour said the method will be easy to scale up.

Electron microscope images of the foam showed partially unzipped outer layers of the nanotubes had bonded to the graphene, which accounted for its strength and resilience. Graphene foam produced without the rebar could support only about 150 times its own weight while retaining the ability to rapidly return to its full height. But rebar graphene irreversibly deformed by about 25 percent when loaded with more than 8,500 times its weight.


Story Source:

Materials provided by Rice University. Original written by Mike Williams. Note: Content may be edited for style and length.


Journal Reference:

  1. Junwei Sha, Rodrigo V. Salvatierra, Pei Dong, Yilun Li, Seoung-Ki Lee, Tuo Wang, Chenhao Zhang, Jibo Zhang, Yongsung Ji, Pulickel M. Ajayan, Jun Lou, Naiqin Zhao, James M. Tour. Three-Dimensional Rebar Graphene. ACS Applied Materials & Interfaces, 2017; DOI: 10.1021/acsami.6b12503

Cite This Page:

Rice University. "Graphene foam gets big and tough: Nanotube-reinforced material can be shaped, is highly conductive." ScienceDaily. ScienceDaily, 14 February 2017. <www.sciencedaily.com/releases/2017/02/170214130456.htm>.
Rice University. (2017, February 14). Graphene foam gets big and tough: Nanotube-reinforced material can be shaped, is highly conductive. ScienceDaily. Retrieved February 25, 2017 from www.sciencedaily.com/releases/2017/02/170214130456.htm
Rice University. "Graphene foam gets big and tough: Nanotube-reinforced material can be shaped, is highly conductive." ScienceDaily. www.sciencedaily.com/releases/2017/02/170214130456.htm (accessed February 25, 2017).