Researchers tap Semtex-related nanotubes to convert heat into electricity

MIT scientists have discovered yet another use for carbon nanotubes: converting heat into electricity.

A paper published by Michael Strano, the Charles and Hilda Roddey associate professor of chemical engineering at the Institute, suggests that the nano-sized tubes could be used to produce batteries with up to 100 times the power density of existing cells.

The paper, published in Nature Materials over the weekend, is called Chemically driven carbon-nano tube-guided thermopower waves. In it, Strano and his colleagues describe how an explosive microscopic shell wrapped around a multi-walled carbon nanotube can be used to push electrons ballistically down the tube's tiny aperture.

"This wave produces a compliment and electrical pulse of disproportionately high specific power," said the paper.

Described as a thermopower wave, it can produce up to 7kW of power per kilogramme, which is an order of magnitude higher than the power density found in modern Lithium-ion batteries. "Such waves of high-powered density may find uses as unique energy sources," the researchers concluded.

Like many potential uses for carbon nanotubes, the technology is still years away from commercial adoption. Nevertheless, it could be used in a wide range of exciting applications, including tiny, self-powered sensors, and smaller body implants. Applications for larger batteries that could power electrical vehicles are presumably also possible.

Bizarrely, the explosive material used at the nanoscale to excite electrons inside the carbon nanotubes is cyclotrimethylene trinitramine. At a larger scale, this is the explosive known as RDX, which forms the basis for many explosives used in demolition applications, such as Semtex. It also forms part of the high explosive component of nuclear weapons, which is used to compress their plutonium core, inducing another, more catastrophic molecular reaction.