Researchers from Rice University have created a ‘seamless’ graphene and nanotube hybrid. The material is probably the best electrode interface material possible for energy storage usages and other related electronics applications, according to the researchers.
The new hybrid material appears as “forests of carbon nanotubes that rise quickly from sheets of graphene to astounding lengths of up to 120 microns. A house on an average plot with the same aspect ratio would rise into space.”
What this means, is that the material has an enormous amount of surface area, which is the primary factor in creating things like energy-storing supercapacitors.
The hybrid is a simple combination of a two-dimensional sheet of graphene with nanotubes, into a seamless three-dimensional structure. The seamless bond is created by the sharing of the electrons of the adjacent carbon atoms in the two materials. This essentially fuses them into one material.
“Many people have tried to attach nanotubes to a metal electrode and it’s never gone very well because they get a little electronic barrier right at the interface,” James Tour, Rice University chemist, and lead researcher on the study, said. “By growing graphene on metal (in this case copper) and then growing nanotubes from the graphene, the electrical contact between the nanotubes and the metal electrode is ohmic. That means electrons see no difference, because it’s all one seamless material.”
“This gives us, effectively, a very high surface area of more than 2,000 square meters per gram of material. It’s a huge number,” said Tour, Rice’s T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science.
According to the researchers, the proof of the material’s hybrid nature are the seven-membered rings located at the point where graphene becomes a nanotube. These rings were predicted in the theoretical description of such a material.
This combination has enormous potential for uses in a variety of different energy storage technologies.
“The performance we see in this study is as good as the best carbon-based supercapacitors that have ever been made,” Tour said. “We’re not really a supercapacitor lab, and still we were able to match the performance because of the quality of the electrode. It’s really remarkable, and it all harkens back to that unique interface.”
Source: Rice University
Image Credits: Tour Group/Rice University