Yes, you know, yarn that weaves into a wristband or sweater.
Except in this case, this is a special yarn consisting of highly flexible micrometer-sized stainless steel filaments, onto which metals are deposited (zinc as the anode, nickel cobalt hydroxide as the cathode). A gel electrolyte is then coated around the entire piece of yarn, turning it into a battery.
This highly conductive yarn battery has a diameter and flexibility similar to that of a piece of cotton yarn. The yarn battery is then woven into fabric and worn as a wristband or other type of clothing to power various electronic devices, such as watches, LEDs, pulse monitors, and other small personal electronics.
The yarn battery is also quite resistant. After bending and twisting for 1,000 cycles, the battery retains 80% and 70% of its initial capacity, respectively. The researchers explain that the capacity loss is due to the formation of cracks on the electrodes when deformed.
To demonstrate the battery, the researchers wove the conductive yarn into a large conductive cloth, which was then used as a wristband battery to power a watch and LED. They expect that the yarn battery will have practical applications in wearable electronics, smart garments and healthcare.
The research team will next focus on making “textile batteries that are washable, waterproof and durable.”
Next time you step out with your camera for an extended photo shoot, don’t forget to wear a spare sweater (woven, of course, with the yarn battery).
We told you about transparent solar cells before. Imagine that whatever you wear in the future–glasses, clothes, shoes–are in fact batteries that can power your cell phone, watch and other personal electronics–who knows, maybe even a personal force field to prevent the elderly from getting hurt when they fall?
In other news, an international research team led by scientists at The University of Texas at Dallas and Hanyang University in South Korea has developed high-tech coiled carbon nanotube yarns that generate electricity when they are stretched or twisted. [ video ]