Small, flexible electronics promise "smart" clothes of the future, such as T-shirts loaded with sensors that can discreetly keep track of your vital signs and check for health problems. Now Huisheng Peng and his colleagues at Fudan University in Shanghai, China, have created a thread-like battery that can be woven into smart textiles to keep them running smoothly.
First, the team created wires made from carbon nanotubes nested inside each other. Some wires were coated with a powder of lithium titanium oxide nanoparticles, and others with lithium manganese oxide. One of each type of wire – representing the battery's positive and negative terminals – were twisted together with a gel electrolyte and a thin strip of non-conducting material separating them.
A 10-centimetre-long piece of this battery weighs just 0.08 grams and can light a string of LEDs for up to a minute, the team reported.
The researchers coiled the battery around an elastic thread to produce a stretchy power source. The threads could be bent and pulled hundreds of times without significant cost to their performance (Angewandte Chemie,doi.org/f2r6pv).
Previous work in South Korea created a cable-shaped battery made of copper and aluminium wire. But the yarn-like battery may be better for textiles because it has no metal components, says Peng.
Ying Chen at Deakin University in Melbourne, Australia, notes that the battery is just a proof of principle for now, since it has a relatively low capacity to store electricity and is expensive to make. But with wearable technology looking set to take off, he says the yarn-like battery is a big advance.