Using Carbon Nanotubes to Produce Electricity

The researchers of Massachusetts Institute of Technology (MIT) have uncovered a new phenomenon of carbon nanotubes. They found that carbon nanotubes discharge powerful waves of electricity under certain circumstances. MIT team named it as thermopower waves. They are pinning their hope on thermopower waves to produce electricity to be utilized in small electrical appliances or maybe in large-scale applications too. This project was funded by the Air Force Office of Scientific Research, and the US National Science Foundation (NSF).This discharge of electricity from carbon nanotubes is a very rare occurrence. Traditionally we derive electricity from water, sun, wind, coal or heat produced by burning of fossil fuels. The thermopower wave, “opens up a new area of energy research, which is rare,” said Michael Stranowho is MIT’s Charles and Hilda Roddey associate professor of Chemical Engineering. His work was published in scientific journal Nature Materials.

Carbon nanotubes are submicroscopic structures. They are just billionths of a meter in diameter. Carbon nanotubes resemble honeycombs. For the past twenty years scientists are focusing their energies on carbon nanotubes, graphene sheets and buckeyballs. They find these three most promising for clean and green energy research. These three substances can be valuable for the medicine, nanotechnology, geoengineering, biology, and for the electronics industry.

Researchers associated with this project find the whole phenomenon quite unusual. They have observed that as the moving pulses of heat pass through the carbon naotubes, electrons also travel along. This movement of electrons is responsible for generation of electric current. Strano says, “There’s something else happening here. We call it electron entrainment since part of the current appears to scale with wave velocity.”

Researchers coated carbon nanotubes with a layer of reactive fuel that can generate heat by decomposing. This fuel was then ignited by a laser beam or high voltage spark at the one end of the nanotube. This ignition resulted in fast moving thermal waves. When this thermal wave enters into carbon nanotube its velocity increases thousand times than the fuel itself. When heat waves contact the thermal coating they produce a temperature of 3,000 kelvins. This ring of heat runs to the length of the tube 10,000 times faster than the normal spread of this chemical reaction. The unusual occurrence is that electrons also travel with the heat inside the tube. Strano says that events like this “have been studied mathematically for more than 100 years” but he was the first to envisage that such waves could be guided by a nanotube or nanowire and that this wave of heat could thrust an electrical current all along that wire.

Strano explains, “There’s something else happening here. We call it electron entrainment, since part of the current appears to scale with wave velocity.” He confirms that the thermal waves are behaving like ocean waves. We have observed that when ocean waves travel they carry the debris on their surface. Strano thinks that this property is responsible for the high power output by the system. Strano suggests the possible use of this discovery. He says that one possible use could be enabling new kinds of ultra-small electronic devices having sensors or treatment devices that would be injected into the body.

Ray Baughman, director of the Nanotech Institute at the University of Texas at Dallas, shares his views regarding the whole project that it “started with a seminal initial idea, which some might find crazy, and provided exciting experimental results, the discovery of new phenomena, deep theoretical understanding, and prospects for applications.” Because it revealed a previously unknown phenomenon, he says, it could open up “an exciting new area of investigation.”