Engineers at the University of California, San Diego, USA, have developed a new type of coating that generates an electrical current from simple contact with water. It is only necessary that the water be mobile and roll over the surface of the plate. This invention could become the basis for new large-scale hydroelectric power plants.
The idea is that when ions, atoms with an electric charge, move along a surface that also has a charge, a voltage will be created between them, and it is already converted into an electric current. The movement of ions is provided due to the movement of the medium in which they are located (water in the form of a wave), rolling over the prepared surface. If this is salty sea water, then ions of different hydroxides are always in excess in it, and it is not difficult to bring a charge to the working surface.
The Californians know-how is that they have created a surface with such a high degree of hydrophobicity that water does not wet it at all and ions do not penetrate into the material. They only slide along the surface, which allows the generation of electric current without interference. To do this, the engineers took a high-purity silicon semiconductor wafer, on the surface of which tiny grooves were etched and filled with synthetic motor oil.
So far, it has been possible to achieve a voltage generation of only 0.05 V, but we are talking about a laboratory setup, where water flows in a thin stream over a tiny substrate. On the scale of at least an ordinary beach, such an installation should already be of commercial interest. After all, this is almost a reference example of green and renewable energy, which does not affect the environment in any way and can generate energy as long as there are waves in the sea.