An international team of researchers led by scientists at the University of Texas at Dallas and Hanyang University in South Korea have developed high-tech yarns that are capable of generating electricity when they’re stretched or twisted. Dubbed “twistron” yarns, the researchers have detailed the possible application of these yarns in a study published in the recent issue of the Science journal.
“The easiest way to think of twistron harvesters is, you have a piece of yarn, you stretch it, and out comes electricity,” explained Dr. Carter Haines, associate research professor in the Alan G. MacDiarmid NanoTech Institute at the University of Texas at Dallas. He’s also the co-lead author of the article.
Carbon nanotubes have been used to construct these yarns. They’re hollow cylinders of carbon that are 10,000 times smaller than a human hair in diameter. These nanotubes were first twist-spun into high-strength, lightweight yarns. In order to make them highly elastic, the researchers introduced so much twist that the yarns coiled together like a rubber band that’s over twisted.
The yarns can generate electricity when they’re either submerged in or coated with an ionically conducting material or electrolyte. That can be a simple mixture of table salt and water.
Dr. Na Li, a research scientist at the NanoTech Institute, added that these yarns are fundamentally supercapacitors. When the carbon nanotube yarn is inserted into an electrolyte bath, the yarns are charged by the electrolyte this eliminating the need for an external battery or voltage like in a normal capacitor.
The researchers were able to generate 250 watters per kilogram of peak electrical power after stretching the coiled twistron yarns 30 times a second. Researchers demonstrated in the lab how a twistron yearn that weighed less than a housefly could power a small LED.
They have demonstrated that the performance is scalable by increasing the twistron diameter and by operating many yarns in parallel.
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