The idea of combing electronics with our clothing has been around for a while, but, so far, it has produced mixed results. Nanotechnology has often been mentioned as an ingredient to add to the electronics-textile mix, to help push concept beyond mere novelty.
One way to bring nanotechnology into electronic textiles is to make the textile itself into a big battery for powering our personal electronics. Two years ago, researchers at the University of California Berkeley pursued this line of research. Their approach was to weave nanowires into the textile and to rely on the piezoelectric properties of the nanowires to develop power. While I have not followed up to see where that research ended up, it did seem a bit complicated—weaving nanowires into a textile sounded like a daunting task.
Now, researchers at University of South Carolina (USC), led by Xiaodong Li, a professor of mechanical engineering, has developed what appears to be a much easier way to make a cotton t-shirt into a supercapacitor.
The technique, which was described in the Wiley journal Advanced Materials, started by soaking a regular cotton t-shirt a in a solution of fluoride. After dying it, the researchers examined the material with infrared spectroscopy and discovered that the cellulose of the cotton t-shirt had been converted into activated carbon. Not only had they made it into activated carbon, but also the t-shirt still maintained its flexibility and could be rolled and folded without breaking.
While the activated carbon now could serve as a capacitor and store electrical charge, Li and post-doctoral associate Lihong Bao decided to take it a step further. They took the individual fibers from the treated t-shirt and coated them with “nanoflowers” of manganese oxide. The result was a “stable, high-performing supercapacitor,” said Li in the USC press release. "By stacking these supercapacitors up, we should be able to charge portable electronic devices such as cell phones."
While Li makes mention of the environmentally friendly chemicals used to impart this capability to a t-shirt, it is perhaps the simplicity of the process that will likely be the most intriguing aspect to manufacturers.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.