Graphene foam gets big and tough

Editor’s note: Links to video and high-resolution images for download appear at the end of this release. 

David Ruth
713-348-6327
david@rice.edu

Mike Williams
713-348-6728
mikewilliams@rice.edu

Graphene foam gets big and tough

Rice University’s nanotube-reinforced material can be shaped, is highly conductive 

HOUSTON – (Feb. 13, 2017) – 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.

Graphene foam invented at Rice University is reinforced with carbon nanotubes. It can hold thousands of times its own weight and still bounce back to its full height.

Graphene foam invented at Rice University is reinforced with carbon nanotubes. It can hold thousands of times its own weight and still bounce back to its full height. Courtesy of the Tour Group

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.

A microscope image of rebar graphene shows carbon shells, multiwalled carbon nanotubes and two-dimensional graphene.

A microscope image of rebar graphene shows carbon shells, multiwalled carbon nanotubes and two-dimensional graphene. Courtesy of the Tour Group

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.

Junwei Sha, a visiting graduate student at Rice and a graduate student at Tianjin University, China, is lead author of the paper. Co-authors from Rice are postdoctoral researchers Rodrigo Salvatierra, Pei Dong and Yongsung Ji; graduate students Yilun Li, Tuo Wang, Chenhao Zhang and Jibo Zhang; former postdoctoral researcher Seoung-Ki Lee; Pulickel Ajayan, chair of the Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry; and Jun Lou, a professor of materials science and nanoengineering. Naiqin Zhao, a professor at Tianjin University and a researcher at the Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, is also a co-author. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative supported the research.

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Read the abstract at http://pubs.acs.org/doi/abs/10.1021/acsami.6b12503

This news release can be found online at https://news.rice.edu/2017/02/13/graphene-foam-gets-big-and-tough/

Follow Rice News and Media Relations via Twitter @RiceUNews

Video:

 

 

 

 

 

 

 

https://youtu.be/rp8OJOfjbec

A piece of rebar graphene stands up to a good soaking in a test at Rice University. (Credit: Tour Group/Rice University)

Related materials:

Rebar strengthens case for graphene: https://news.rice.edu/2014/04/04/rebar-strengthens-case-for-graphene/

The Tour Group: http://tournas.rice.edu/website/

Rice Department of Chemistry: http://www.chem.rice.edu

Wiess School of Natural Sciences: http://natsci.rice.edu

Images for download:

 

 

 

 

 

https://news.rice.edu/files/2017/02/0213_REBAR-1-WEB-1ebsuu3.jpg

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)

 

 

 

 

 

https://news.rice.edu/files/2017/02/0213_REBAR-2-WEB-1gp7drb.jpg

A microscope image of rebar graphene created at Rice University shows carbon shells, multiwalled carbon nanotubes and two-dimensional graphene. The material can support more than 3,000 times its own weight and quickly return to its original dimensions. (Credit: Tour Group/Rice University)

 

 

 

 

 

https://news.rice.edu/files/2017/02/0213_REBAR-3-WEB-1ka5v3h.jpg

Graphene is marked in blue and carbon nanotubes in orange in this microscope image of rebar graphene created at Rice University. The conductive material can be formed into any shape. (Credit: Tour Group/Rice University)

 

 

 

 

https://news.rice.edu/files/2017/02/0213_REBAR-4-WEB-usi60u.jpg

Graphene foam invented at Rice University is reinforced with carbon nanotubes. It can hold thousands of times its own weight and still bounce back to its full height. (Credit: Tour Group/Rice University)

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About Mike Williams

Mike Williams is a senior media relations specialist in Rice University's Office of Public Affairs.