Charging our clothes to credit cards is nothing new. Now our clothes may be doing the charging.
Scientists at the University of South Carolina (USC) have devised a way to turn the material in a cotton T-shirt into a source of electrical power. They envision a future where electronics are part of our wardrobe.
A few years back, my daughter haunted me for a hoodie with built-in ear buds, a novelty garment that allowed her to look stylin’ and also stay connected to her ubiquitous digital music device. USC Professor Xiaodong Li, the tee-shirt project mastermind, takes tech fashion to new heights, anticipating an emerging need for flexible energy storage: new methods of juicing our technical tools in remote locations, off the grid, and on the go.
Modified fabric in tee shirts can store electrical charges.
Li and his associate Lihong Bao described how they converted a simple cotton tee-shirt into an electrical power source, in a recent report in the journal Advance Materials. The team soaked a conventional shirt in a flouride solution. They dried it, then baked it at super-high temperature in an oxygen-free oven to prevent the material from burning.
The altered material remained flexible; it could be draped and folded. Inspecting the cooked cloth via infrared spectroscopy, they found the resulting fabric fibers had been converted from cellulose to activated carbon, a natural repository for electricity.
Li and Bao then painted the individual fibers of the cloth with a nanometer-thick coat of manganese oxide, stepping up the fabric’s energy storage capability.
The researchers discovered that small swatches of the flexible material, which they named carbon textile, acts as a capacitor. Capacitors perform like tiny storage batteries that charge and discharge rapidly. They can be made from many different materials, and virtually every electrical and electronic system uses them.
Tests proved their hybrid supercapacitors were stable and resilient: after thousands of charge-discharge cycles, performance never decreased more than 5% below initial capacity. Their carbon textile boasts a particularly high energy storage density. “By stacking these supercapacitors up, we should be able to charge portable electronic devices such as cell phones,” Li said.
Maybe our clothes will become self-sufficient: power our irons and washers?
Li told the BBC,”One day our cotton T-shirts could have more functions; for example, a flexible energy storage device that could charge your cell phone or your iPad. We will soon see roll-up cell phones and laptop computers on the market,” he said, “but a flexible energy storage device is needed to make this possible.”
Li is particularly pleased to have improved on the means by which activated carbon fibers are usually obtained. “Previous methods used oil or environmentally unfriendly chemicals as starting materials,” he said. “Those processes are complicated and produce harmful side products. Our method is a very inexpensive, green process.”
Image of colorful tee-shirts by Shutterstock