Researchers have shaped a rechargeable zinc-ion battery into an elastic yarn that churns out power when bent, stretched, washed with water, and even cut.
The zinc yarn battery could be woven into washable sensor-laden smart clothes and integrated into commercial textiles to power wearable displays, electronics, and medical implants.
The yarn joins a line-up of innovative flexible energy-generating and -storing devices that can be integrated into power fabrics. The list includes solar cell ribbons that can be woven into fabrics, knittable supercapacitors, and power-generating yarns that harvest mechanical energy or the triboelectric effect to generate power.
Some researchers have tried to make flexible versions of the workhorse zinc-manganese alkaline battery because of its proven high capacity, low cost, and safety. But these flexible versions have had low capacities. Plus these primary batteries can’t be recharged. But researchers have recently come up with high-performance rechargeable zinc-ion batteries.
Chunyi Zhi of the City University of Hong Kong and his colleagues made their thread-like rechargeable zinc battery by twisting carbon nanotube fibers into yarn. They coat one piece of yarn with zinc to make an anode and another with manganese dioxide to serve as a cathode. Then they wind the two yarn pieces on an elastic fiber, soak it with a commonly used water-absorbing gel, and encase the device in elastic silicone and a water repellant.