This Special Material Can Generate Electricity From Falling Rain Drops

Energy will likely be the most valuable resource in the long term — a fact that is already becoming apparent. As climate change increases in severity, we’ll need to rely more on renewable sources of energy. Water has been a major source of that energy for centuries, and the first hydroelectric power generation scheme was developed in the 19th century. Unfortunately, hydroelectric dams come with problems of their own, including both environmental and sociopolitical concerns. But a special new material that can generate electricity from falling drops of rain may soon provide a practical way to charge consumer electronics.

This material was recently described in a study published by an international team of material scientists and engineers led by Zuankai Wang, a professor of mechanical engineering at The City University of Hong Kong. It dramatically improves upon previous research which found that dropping water on particular materials could generate electricity. The process works a bit like a battery, but with the water droplets themselves acting as the resistor. Each time a drop of water splashes against the material, it spreads across and imparts a small electric charge. In the past, that has been so small that it wasn’t practical to harvest, but this new material is much more efficient.

The researchers fabricated this material from a combination of PTFE (PolyTetraFluoroEthylene) and aluminum that is deposited on a glass substrate coated in a thin layer of ITO (Indium Tin Oxide). The resulting material is optically transparent apart from the embedded electrodes. A single drop of water is enough to illuminate 100 LEDs, and the efficiency increases when with the number of drops. This could make it possible to create umbrellas that charge your smart phone, or even building windows that help supplement traditional electricity sources. There are, of course, still challenges to overcome before we’ll see this material in the real world, but it’s definitely a major step forward for sustainability.