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Fabric Batteries for Clothes that Can Conduct Electricity

Breakthrough:
A carbon-nanotube dye that can turn fabrics into batteries to make clothes that conduct electricity.

Business:
Department of Materials Science and Engineering, Stanford University, United States

The Story:
If you want to charge your cell phone just plug in your jeans!

All you have to do is dip a piece of fabric in a solution infused with tiny tubes of carbon, and it turns into a battery. Simply coating a piece of cotton or polyester with the formulation transforms it into a high performance energy storage device that is a boost to the emerging field of wearable electronics.

A Breakthrough in Wearable Electronics

The approach was first demonstrated by Stanford University in 2009 on plain copying paper, but now it has been applied to textiles for the first time. “Wearable electronics represent a developing new class of materials... which allow for many applications and designs previously impossible with traditional electronics technologies," the authors wrote in the journal Nano Letters.

The research could pave the way to unobtrusive wearable electronics for use in health monitoring systems, the fashion and gaming industries, and for any application that requires computers.

A team led by Prof Yi Ciu incorporated single-walled carbon nanotubes - cylinders of carbon about a billionth of a meter across – into the textiles by a simple dying process.

The dye is made by dispersing carbon nanotubes in water and using sodium dodecylbenzenesulphonate as a surfactant. The material is dipped into the mixture and then dried in an oven at 120 degrees Celsius for ten minutes to remove water.

There have been a number of research efforts in recent years that have demonstrated the possibility of electronics on flexible and transparent surfaces, but applying it to ordinary fabrics has provide problematic – until now.

Supercharged Clothes

The method is the same as that highlighted in Ciu’s previous work with plain paper; - the small diameter of the nanotubes make it easy for them to stick to the interwoven fibers of fabric due to van der Waals forces and hydrogen bonding, and an electrical connection is maintained across the substrate.

The conductivity of the material is increased by simple mechanical pressing and boosted still further by increases in the number of dipping and drying steps. The fabric maintains its properties when stretched and pulled and there is no decrease in conductivity - even when it is rinsed in water.

Cotton proved to be up to 3 times better for energy storage than man-made fibers as its porous nature allowed for better ion transport.

Commercialization

Experts believe the technology could be commercialized in a short space of time, and that its uses will not be limited to just energy storage devices. According to Peidong Yang, a professor of chemistry at the University of California-Berkeley it has the potential to be a low-cost flexible electrode for any electrical device.

The Stanford researchers say the next stages of their research are to use the approach with materials that can store more energy, and then demonstrate how to integrate the textile energy storage devices into clothes.

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