Nano cable: This cable, made of carbon nanotubes, can carry as much electrical current as a copper wire.

“It is a testament to how mature these materials are becoming that they are able to measure conductivities that now exceed common metals,” says Michael Strano, a professor of chemical engineering at MIT who was not involved with the work. Surpassing metals, he says, “represents a milestone.”

“This is very exciting, especially considering the enormous importance of decreasing the weight of [electrical] cables in airplanes and cars” to improve fuel efficiency, says Ray Baughman, director of the NanoTech Institute and professor of chemistry at the University of Texas at Dallas. Baughman was not involved with the work.

Aerospace giant Boeing is among the companies supporting the Rice group. Other collaborators and supporters include Chevron, the U.S. Department of Energy, and NanoRidge Materials of Houston.

“The goal is to make an engineered product,” says Rice’s Barrera. “We believe what we’ve been able to do is scalable to continuous production methods.” The group has mapped out how this would be done on a manufacturing line and is currently exploring commercialization with various companies, though they have not disclosed any deals.

Though the cables are now good enough to begin thinking seriously about commercial applications, Ajayan wants to make them even better. Ajayan notes that, so far, they’ve only tested the double-walled cables’ ability to carry alternating current. Electricity is transmitted over long distances in the form of alternating current. A separate goal, Ajayan says, is to make the cables even more conductive than copper. One way to do this is to make workable cables from single-walled carbon nanotubes, which are inherently more conductive, but have been difficult to spin into fibers.