A new finding by researchers at Duke University and Michigan State University could provide an excellent stretch of power for wearable electronics. Supercapacitors are known for their excellent power density, which can charge and discharge large amounts of energy quickly and have a longer life than chemical batteries, which often have the advantage of storing more energy.
The team set out to develop a truly flexible power supply for the wearables they are working on, with the goal of developing innovative devices that can withstand mechanical deformations such as stretching, twisting or bending without compromising performance. If the power supply for the stretchable electronic device is not scalable, the entire device system is constrained to non-scalable.
The team used a design that first created a small “carbon nanotube forest” on a silicon chip, with millions of nanotubes about 20-30 micrometers high in small pieces about 15 nanometers in diameter. Both ends are covered with a gold nanofilm, which reduces the resistance of the final device and allows it to transmit charge faster than previously designed.
Place its golden face down on an elastic substrate that stretches to four times its normal length under tension. Once opened, the tension is released, and the whole thing is wrinkled, squeezing the nanotube “trees” in the “forest” together at a higher density. Finally, the nanotube “forest” is filled with gel electrolytes that capture electrons on the surface of nanotubes. At this point, the two electrodes are clamped together, a voltage is applied, and all electrons are transferred from one side to the other, where they can be stored and released as energy.