A team of researchers from the University of Texas at Dallas and Hanyang University in South Korea has developed a new type of yarn spun from carbon nanotubes for energy harvesting.
As compared to the earlier electricity-generating textile attempts, this yarn offers more than 100 times the electrical power. The study was published in the journal “Science” this week. The yarn is named as “twist on” yarn.
It has been a long time the scientists have been trying to tap the unused energy available abundantly around us. The very common examples can be energy from the pressure exerted by the footfall, heat generated and emitted into the air by heavy machinery in manufacturing industries etc. It is not that such energy can’t be harvested but the problem today is the feasibility of it. To highlight – the piezoelectric generators can harvest energy from stresses and strains, whereas the triboelectric generators can harvest energy from friction, but the main issue is their low efficiency, costly investments, so these won’t be cost effective.
The idea used behind these carbon nanotubes harvesting energy is very simple. They collected carbon nanotubes and spun them into a thread, much similar to the way you would spin wool. There are many ways used for spinning threads, and the method chosen here created an internal structure which distributed the stress evenly amongst all the nanotubes. Then it was twisted until it formed a coil which looked similar to the ones like the headset cord of old land-line telephones. Later this coil was stretched and due to the internal strain and friction, charges were liberated from these carbon nanotubes. To harvest these the entire thing was dipped in a water with dissolved ions and the charges were attracted to the nearby electrodes.
The results were highly impressive, when the yarn was under peak strain, it pumped out 250 watts per kilogram of energy. The yarn was able to sustain up to 30 stretch/relax cycles a second. Across one full cycle, the yarn generated more than 40 joules of energy, buy this energy was distributed unevenly. A lot more study needs to be carried out before commercial use of this new research, surely this can be a cheap way of harvesting energy!