(Image by enot-poloskun/Getty Images)Engineers at MIT have discovered a new way to generate electricity, and you can thank our old friend, carbon nanotubes. These microscopic tubes of carbon atoms were the hottest thing in material science for a few years, and they could be making a comeback. By grinding up nanotubes and dipping them in special solvents, the team showed it’s possible to generate enough current to run important electrochemical reactions and maybe one day to power super-small devices.
According to MIT chemical engineering engineer Michael Strano, this method of generating energy is entirely new. It’s especially intriguing because you don’t need any external wiring. Simply flowing an appropriately electron-poor solvent over the treated nanotubes will generate a current. The study, which appears in the journal Nature Communications, focuses on one application in particular: the oxidation of alcohol into an aldehyde or a ketone.
This work builds on research Strano did in 2010, demonstrating that nanotubes could create “thermopower waves.” That experiment showed nanotubes could generate electricity when coated with fuel and hit with heat pulses. Now, Strano’s team has found that coating one end of a nanotube with a Teflon-like polymer creates a charge imbalance that helps electrons flow from the coated to the uncoated part of the tube.
To leverage this property of nanotubes, the team ground them up into tiny pieces and turned them into a sort of nanotube paper. One side of the sheet had the polymer coating, and the other didn’t. Then, they cut out small chunks measuring 250 micrometers across and submerged them in acetonitrile. Sure enough, the solvent adheres to the uncoated surface and pulls electrons away from the tubes.
The particles can form arrays of several hundred that fit inside a test tube, and each one can generate 0.7 volts of electricity. This so-called “packed bed” reactor was powerful enough to drive alcohol oxidation. While important in chemical engineering, it’s not usually done with electrochemistry because it would require high external current. That’s not the case with the nanotube particle array.
In the future, Strano hopes to develop reactors that can build polymers from raw materials like carbon dioxide. Down the road, this system could even generate power for nano-scale robots and other devices that are too small for traditional power mechanisms.