If you've ever taken a peek below the surface of the ocean, you'll have seen seaweed waving back and forth in the current. Scientists from China's Dalian Maritime University have now utilized that same motion in an underwater energy-harvesting device.
Developed by a team led by Minyi Xu and Zhong Lin Wang, the seaweed-inspired tool is a type of triboelectric nanogenerator, or TENG for short.
TENGs take advantage of the triboelectric effect, a phenomenon in which an electrical charge accumulates in one material after it's separated from another material with which it was in contact. It's what's responsible for the static charge that occurs when you're combing your hair.
In this particular device, a thin layer of porous sponge material is sandwiched between a couple of 1.5 by 3-inch (38 by 76-mm) strips made of two different polymers. Those strips are both coated in a conductive ink, with the sponge creating an air gap between them. The whole thing is sealed with waterproof tape.
When the resulting TENG bends back and forth in even a relatively weak underwater current, the two polymer strips squeeze through the sponge to intermittently come in and out of contact with one another, generating an electrical current in the process. In wave tank tests, it was shown that multiple TENGs could be used to continuously power devices such as marine environmental sensors, eliminating the need to perform battery-changes.
The device is demonstrated in the following video, and is described in a paper that was recently published in the journal ACS Nano.
Source: American Chemical Society