We’ve written about the possibilities that carbon nanotubes can unlock before, and now, an intrepid team of MIT scientists have discovered a never before known phenomenon using the tubes, which are essentially rolled up sheets of graphene. The occurence, which researchers are calling “thermopower waves” causes powerful waves of energy to speed down the tubes. Michael Strano, MIT’s Charles and Hilda Roddey Associate Professor of Chemical Engineering says that the discovery “opens up a new area of energy research, which is rare,” and according to MIT, the new development could pave the road to a totally new way of producing electricity.
If you’ve never heard of carbon nanotubes before, they’re essentially tiny (and we mean submicroscopic) hollow tubes made of an interconnected network of carbon atoms. To come to their discovery, scientists at MIT coated the nanotubes with a reactive fuel and then lit one end, causing a fast-moving thermal wave to speed down the length of the tube. The heat from the fuel rises to a temperature of 3,000 kelvins, and can speed along the tube 10,000 times faster than the normal spread of this chemical reaction. The heat also pushes electrons down the tube which creates a substantial electrical current. Of the breakthrough, Strano says, “lo and behold, we were really surprised by the size of the resulting voltage peak” that propagated along the wire.
The system can output energy (in proportion to its weight) about 100 x greater than an equivalent weight lithium-ion battery. Strano explains that the high power created by the system is due to the fact that the wave appears to be transporting the electrical charge carriers kind of like an ocean wave could pick up and carry debris along its surface.
So what real-world applications could thermopower waves be used for? Strano says that one possibility would be ultra-small electronic devices since the nanotubes are so tiny (although they could be made into larger arrays to power larger electronics). Or it could lead to “environmental sensors that could be scattered like dust in the air,” he says. Unlike batteries that lose power while they’re not being used, these devices could, in theory, maintain their charge indefinitely while idle.
Another idea that the scientists are playing with is that by using different kinds of reactive materials to coat the tubes, the resulting wave front could oscillate, producing an alternating current. Since radio waves such as cell phone signals are based on alternating current, this part of the discovery could open up an additional host of uses.