Researchers create battery that can be stretched, twisted and washed

The battery could be used in watches, medical patches, and smart clothing

(Kai Jacobson)

A new kind of battery that is both flexible and washable has been developed by researchers.

The battery can be twisted and stretched to twice its normal length while also being machine washable.

“Wearable electronics are a big market and stretchable batteries are essential to their development,” says Dr Ngoc Tan Nguyen, a postdoctoral fellow at the University of British Columbia’s faculty of applied science. “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.”

In conventional batteries, the internal layers are encased in a hard exterior , but for this new battery the researchers ground down they key chemicals - zinc and manganese dioxide – and embedded them in a rubbery polymer. These chemicals are safer than lithium-ion batteries which produce toxic chemicals when they break down.

The completed battery is made up of several ultra-thin layers of these plastics, creating an airtight and waterproof seal.

(Kai Jacobson)

“We put our prototypes through an actual laundry cycle in both home and commercial-grade washing machines. They came out intact and functional and that’s how we know this battery is truly resilient,” says PhD student Bahar Iranpour. So far, the battery has endured 39 wash cycles.

The researchers are now looking to improve the battery’s power output and life cycle, with the expectation that, when it reaches the consumer market, it could cost the same as a normal rechargeable battery.

As well as watches and medical patches, the battery could be used in clothing that could change colour or temperature.

The battery is described in a new paper published recently in Advanced Energy Materials.