Flexible Battery Opens the Way for Wearable Devices

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Wearable devices need power. Wearable electronics are a big market and stretchable batteries are essential to their development. University of British Columbia researchers have created what could be the first battery that is both flexible and washable. It works even when twisted or stretched, or after being tossed in the laundry.

Applications include watches and patches for measuring vital signs, as well as the possibility to integrate the battery with clothing that can actively change color or temperature.

The battery 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 then embedding them in rubbery plastic, or polymer. The battery comprises 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, according to news.ubc.ca.

The choice of zinc and manganese dioxide chemistry also confers another important advantage. As the devices are expected to be worn next to the skin, these materials are safer than lithium-ion batteries, which can produce toxic compounds when they break, say the researchers.

Work is underway to increase the battery’s power output and cycle life. The researchers believe that when the new battery is ready for consumers, it could cost the same as an ordinary rechargeable battery.

The findings were published in Advanced Energy Materials.