Wearable technology, CU Boulder study

A thermoelectric wearable device worn as a ring

Researchers at the University of Colorado Boulder have developed a new, low-cost wearable device that generates power from a user's body heat, thus converting people into batteries.

The device is made from a stretchy material called polyimine and can be worn as a ring, bracelet or any other accessory that touches a persons skin. The scientists place a stick of thin thermoelectric chips into the polyimine base and then connect them using liquid metal wires.

When worn, the device uses the thermoelectric generators to convert the body's internal temperature into electricity.

"In the future, we want to be able to power your wearable electronics without having to include a battery," said Jianliang Xiao, an associate professor in the Paul M. Randy Department of Mechanical Engineering at CU Boulder, in a media release. 

Although the the device cannot currently generate the same amount of energy as most existing batteries, it produces 1 volt of energy for every square centimes of skin space, which is enough to power electronics like watches or fitness trackers. 

Researchers say if they produced a larger model similar to a traditional sports wristband, someone who takes a brisk walk could produce around 5 volts of electricity. In the past they have experimented with similar thermoelectric devices, but this new one is stretchy and can heal itself when damaged.

"If your device tears, for example, you can pinch together the broken ends, and they’ll seal back up in just a few minutes," researchers said. "And when you’re done with the device, you can dunk it into a special solution that will separate out the electronic components and dissolve the polyimine base—each and every one of those ingredients can then be reused."

Another advantage to the new device is that it is fully recyclable, making it a new, cleaner alternative to traditional electronics that researchers say will soon hopefully be affordable to all.

"We're trying to make our devices as cheap and reliable as possible, while also having as close to zero impact on the environment as possible," Xiao said.