Liquid Metal Encased in Hydrogel Makes a Promising Energy-Harvesting Device
Freeman writes:
Liquid metal encased in hydrogel makes a promising energy-harvesting device:
Scientists at North Carolina State University have developed a flexible, stretchy energy-harvesting device solely out of biocompatible soft materials: liquid metal and soft polymers known as hydrogels. It produces small amounts of electricity comparable to other energy-harvesting technologies, and it can also operate in water as well as air, according to the team's recent paper published in the journal Advanced Materials. The team thinks the new NCSU device holds promise for powering wearable devices, charging them spontaneously with no need for an external power source.
"Mechanical energy-such as the kinetic energy of wind, waves, body movement and vibrations from motors-is abundant," said co-author Michael Dickey, a chemical and bimolecular engineer at NCSU. "We have created a device that can turn this type of mechanical motion into electricity. And one of its remarkable attributes is that it works perfectly well underwater."
The NCSU scientists were particularly inspired by a 2013 paper by Korean researchers. The 2013 researchers found they could harvest energy from an electrical double-layer capacitor (ELCD) by depressing arrays of water droplets sandwiched between two rigid electrodes, thereby spontaneously charging the capacitor.
[...] The key proved to be a liquid-metal alloy of gallium and indium, per Dickey, which is then encased in a water-absorbent hydrogel. The dissolved salts in the water (ions) congregate on the metallic surface, forming an electrical double layer akin to a capacitor. Deforming the liquid metal increases the area, and the greater the surface area, the greater the induced charge.
Journal Reference:
Veenasri Vallem, Erin Roosa, Tyler Ledinh, et al. A Soft VariableArea ElectricalDoubleLayer Energy Harvester, Advanced Materials (DOI: 10.1002/adma.202103142)
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