Researchers have given the term “power plant” a new meaning with new leaf-like energy generators that convert the energy from falling raindrops and blowing wind into electricity. The device, reported in the journal ACS Sustainable Chemistry & Engineering, generates enough power to light up 10 LEDs, at least for short bursts of time.
Small, sustainable power sources will be necessary to power the network of sensors used in smart homes and autonomous vehicles, and for environmental monitoring. Energy harvesters that scavenge energy from the environment are ideal for the task. But their output so far has been too low for driving sensor electronics. Researchers have been trying to make devices that harvest energy from multiple sources—such as sun and rain—to boost power output.
So Northeastern University electrical and computer engineering professor Ravindra Dahiya and his colleagues made devices that harvest energy from wind and rain. They started with a triboelectric nanogenerator (TENG), which converts motion into electricity by harnessing the phenomenon behind static electricity. TENGs produce power from the charges that build up when dissimilar materials contact each other and then separate.
The team carefully chose the materials for the TENG to maximize power output. They made the device by sandwiching tiny nylon fibers between two sheets of Teflon and copper electrodes. When wind ruffles the material, the Teflon and nylon layers touch and separate, producing electricity.
The other device is a droplet-based energy generator (DEG), which the engineers made by adding a water-repelling layer on the top Teflon sheet of a TENG. To do that, they roughened the Teflon by rubbing it with sandpaper, and coated it with a commercial waterproofing solution. The DEG converts the kinetic energy from raindrops into electricity.
Finally, the researchers attached the DEG on top of the TENG, cut the material into leaf shapes, and incorporated the leaves into an artificial plant. In laboratory tests, exposing the leaf-shaped generators to conditions mimicking wind and rain generated enough power to make 10 LED lights turn on in short flickers.
“Such proof-of-concept devices could be further advanced to develop energy-harvesting artificial trees to produce clean energy everywhere from gentle winds and rain drops,” the researchers write
Source: Guanbo Min et al. Multisource Energy Harvester on Textile and Plants for Clean Energy Generation from Wind and Rainwater Droplets. ACS Sustainable Chem. Eng. 2024.
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