A special yarn made from carbon nanotubes has been developed to generate electricity when twisted or stretched, converting mechanical energy into electricity. This new technology could power wearable or small medical devices without the use of batteries.
The twisted yarn has a sufficient number of twists in it such that when stretched out, the effective volume of the nanotubes decreases making their electrons come nearer to each other producing an increase in voltage on the yarn’s charge, enabling the harvesting of electricity.
A twisted yarn that is stretched 30 times per second can generate a power of 250 watts per kilogram of the yarn. This rate is over a hundred times higher than other energy-harvesting fabric yet developed.
The team that developed this twisted yarn is composed of international researchers, led by the scientists at the University of Texas, Dallas. They said that the performance of twisted yarn can be improved by increasing its diameter and deploying multiple strands of it in parallel, but the cost of producing the yarn limits the scaling up of this technology. Still, the twisted yarn finds its promising application in small devices such as sensors and sensor communications.
“If our twistron harvesters could be made less expensively, they might ultimately be able to harvest the enormous amount of energy available from ocean waves.
Based on demonstrated average power output, just 31 milligrams of carbon nanotube yarn harvester could provide the electrical energy needed to transmit a 2-kilobyte packet of data over a 100-meter radius every 10 seconds for the Internet of Things,” stated study co-author Dr. Ray Baughman, director of Nanotech Institute.