Ultra-thin layers of rust generate electricity from flowing water
There are many ways to generate electricity -- batteries, solar panels, wind turbines, and hydroelectric dams, to name a few examples. .... And now there's rust.
New research conducted by scientists at Caltech and Northwestern University shows that thin films of rust -- iron oxide -- can generate electricity when saltwater flows over them. These films represent an entirely new way of generating electricity and could be used to develop new forms of sustainable power production.
Interactions between metal compounds and saltwater often generate electricity, but this is usually the result of a chemical reaction in which one or more compounds are converted to new compounds. Reactions like these are what is at work inside batteries.
In contrast, the phenomenon discovered by Tom Miller, Caltech professor of chemistry, and Franz Geiger, Dow Professor of Chemistry at Northwestern, does not involve chemical reactions, but rather converts the kinetic energy of flowing saltwater into electricity.
The phenomenon, the electrokinetic effect, has been observed before in thin films of graphene -- sheets of carbon atoms arranged in a hexagonal lattice -- and it is remarkably efficient. The effect is around 30 percent efficient at converting kinetic energy into electricity. For reference, the best solar panels are only about 20 percent efficient.
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