Researchers at the University of British Columbia (UBC) have created what could be the first battery that is both flexible and washable, a device that will work even when twisted or stretched to twice its normal length, or after being laundered.
According to information provided by UBC, the battery, which was developed by a postdoctoral fellow at UBC’s faculty of applied science, Dr. Ngoc Tan Nguyen, and his colleagues, offers a number of engineering advances. In normal batteries, the internal layers are hard materials encased in a rigid exterior. The UBC team made the key compounds—in this case, zinc and manganese dioxide—stretchable by grinding them into small pieces and embedding them in a polymer.
The battery is comprised of several ultra-thin layers of these polymers wrapped inside a casing of the same polymer. This construction creates an airtight, waterproof seal that ensures the integrity of the battery through repeated use.
“Wearable electronics are a big market and stretchable batteries are essential to their development,” says Dr. Nguyen. “However, up until now, stretchable batteries have not been washable. This is a critical addition if they are to withstand the demands of everyday use.”
It was team member, Ph.D. student Bahar Iranpour, who suggested throwing the battery in the wash to test its seal. So far, the battery has withstood 39 wash cycles and the team expects to further improve its durability as they continue to develop the technology.
The choice of zinc and manganese dioxide chemistry also confers another important advantage. “We went with zinc-manganese because for devices worn next to the skin, it’s a safer chemistry than lithium-ion batteries, which can produce toxic compounds when they break,” says Nguyen.
Work is under way to increase the battery’s power output and cycle life, but already the innovation has attracted commercial interest. The researchers believe that when the new battery is ready for consumers, it could cost the same as an ordinary rechargeable battery.
The battery is described in a paper published recently in Advanced Energy Materials.