Twisted energy
Dmitrii Blium
Researchers at North Carolina State University have created a soft and stretchable device that converts movement into electricity and can work in wet environments.
Technology
The heart of the energy harvester is a liquid metal alloy of gallium and indium. The alloy is encased in a hydrogel - a soft, elastic polymer swollen with water.
The water in the hydrogel contains dissolved salts called ions. The ions assemble at the surface of the metal, which can induce a charge in the metal. Increasing the area of the metal provides more surface to attract a charge. That generates electricity captured by a wire attached to the device.
The hydrogel is elastic enough to be stretched to five times its original length. That makes it versatile for harvesting mechanical energy, such as any motion like squishing, stretching, and twisting.
Experiments have shown that deforming the device by only a few millimeters generates a power density comparable to several popular classes of energy harvesting technologies.
The keystone difference is that other technologies do not work well in wet environments. The developers believe that this unique feature may enable applications from biomedical settings to athletic wear to marine environments. Plus, the device is simple to make (you can see that from the video).
Future
The researchers already have two related projects going on.
One project is using the technology to power wearable devices by increasing the harvester's power output. The second one evaluates how to harvest wave power from the ocean.
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