A completely new way to generate electricity

It is not often you get to write a title like the one above. The main methods of generating electricity have been know for years, decades or even centuries. Over that time they have been refined, redesigned, rebuilt with better materials and more accurate construction, but the basic principles behind the energy generation remained the same.

Now a team of scientists from MIT have taken a new approach to electricity generation through the way materials interact with liquids. The materials in question are carbon nanotubes. This is no surprise, as since they were first discovered they have been touted as a wonder material that will help to solve many of humanity’s problems. Though, up till now, they don’t seem to have made a real breakthrough into everyday use. The MIT researchers made a solvent flow through a bed of these particles, which draws electrons out of the particles. In the paper written by the researchers, they detailed how they used the electricity generated to drive a reaction known as alcohol oxidation. Alcohol oxidation is an organic chemical reaction that is often used in the chemical industry.

The senior author of the new paper is Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. Strano has been researching carbon nanotubes for well over a decade. In 2010 he demonstrated that carbon nanotubes can generate “thermopower waves. This is an effect when a carbon nanotube is coated with a layer of fuel, which moves pulses of heat along the tube, creating an electrical current. This research led to further advancements, such as when part of a nanotube is coated with a Teflon-like polymer, electrons can flow from the coated to the uncoated part of the tube. This effect generates an electrical current. If the particles are submerged in a solvent that is needs electrons, then the electrons are drawn out.

To use the discovery in practice, the researchers ground up the carbon nanotubes and then formed them into a sheet structure. They then coated one side of the sheet with a Teflon-like polymer. Then, small particles of 250 microns by 250 microns were cut from the sheet. The particles are submerged in an organic solvent, which sticks to the uncoated surface of the particles and begins pulling electrons out of them without the need for external wires to to drive the electrochemical reaction.

This version of the particles generate about 0.7 volts of electricity per particle. For the study, the researchers also formed arrays of hundreds of particles in a small test tube. The resulting “packed bed” reactor generated enough energy to power an alcohol oxidation chemical reaction. This reaction converts an alcohol to an aldehyde or a ketone. This reaction usually needs too much external power using electrochemistry.

In the future, Strano hopes this kind of energy generation can be used to build polymers with obnly carbon dioxide as a starting material. He has already created polymers that can regenerate themselves using carbon dioxide as a building material, in a process powered by solar energy.

In the longer term future, the approach could also be used to power micro- or nanoscale robots. Strano’s lab has already begun building robots at that scale, which could one day be used as diagnostic or environmental sensors using only scavenged energy from the environment.

The research was funded by the U.S. Department of Energy and a seed grant from the MIT Energy Initiative.