“We wear fabric every day,” he added. “One day, our cotton T-shirts could have more functions.”
Li and a fellow researcher in his lab, Lihong Bao, bought a cotton T-shirt from a local discount store. They soaked it in fluoride, dried it, then baked it in an oven without any oxygen, to prevent the T-shirt from burning. Despite the baking, the fabric remained flexible. [Science Fashion Runs the Gamut From Pretty to Precise]
The researchers examined the baked shirt and found that the cotton fibers had turned into activated carbon, similar to the carbon in water and air filters. They also found the activated carbon fabric could store electrical charge as a capacitor, an electrical component that’s found in most devices.
To improve the shirt’s electricity-storing ability, the researchers coated the T-shirt fibers with a layer of manganese oxide one nanometer thick, or about 1/1000th the thickness of a human hair. A second analysis showed the manganese oxide-covered fibers worked as a more efficient capacitor than the treated, toasted cotton alone.
“This created a stable, high-performing supercapacitor,” Li said. The fabric capacitor could charge and discharge thousands of times while losing only 5% of its performance, Li and Bao discovered.
Their method for making the fabric capacitor is inexpensive and doesn’t use environmentally harmful chemicals, Li said.
Li’s is just one of several labs working on creating fabric-based electronics that could turn into wearable devices. The research could lead to coat sleeves and couch arms that act as controls for electronics, such as music players and thermostats, or “smart clothes” that monitor people’s health.