Wearable device turns the body into a battery

1 min read

Researchers in the US have developed a low-cost wearable device that transforms the human body into a biological battery.

wearable device
A thermoelectric power generator worn as a ring. Credit: Xiao Lab

Published in the journal Science Advances, the study explored how the team’s stretchy wearable device can tap into an individual's natural heat by employing thermoelectric generators to covert the body’s internal temperature into electricity.

The team at University of Colorado Boulder hope to be able to power wearable electronics in future without having to include a battery, explained the paper’s senior author Jianliang Xiao, an associate mechanical engineering professor at CU Boulder.

According to the researchers, their devices generate around one volt of energy for every square cm of skin - less voltage per area than what most existing batteries provide, but enough to power electronics like watches or fitness trackers. The device can be worn like a ring, bracelet or any other accessory that touches the skin and can heal itself when damaged as well as being fully recyclable, the team confirmed.

Xiao and his colleagues have previously experimented with designing a wearable device that looks and behaves much like real human skin, however the android epidermis had to be connected to an external power source to work until now. 

'Electronic skin' is recyclable alternative to wearable devices

The group’s latest innovation began with a base made out of stretchy polyimine. The scientists then stuck a series of thin thermoelectric chips into this material, connecting them all with liquid metal wires.

“Our design makes the whole system stretchable without introducing much strain to the thermoelectric material, which can be really brittle,” Xiao said in a statement. “The thermoelectric generators are in close contact with the human body, and they can use the heat that would normally be dissipated into the environment.”

He added that power can easily be boosted by adding in more blocks of generators, comparing the design to ‘a bunch of small Lego pieces’ whereby smaller units are combined to make a large structure allowing for flexible customisation.

Similar to the electronic skin, the new devices are as resilient as biological tissue, the team said. If the device tears, the broken ends can be pinched together and will seal back up in minutes, for example. When finished with the device, it can be immersed into a special solution that separates the electronic components and dissolves the polyimine base, allowing the components to be reused. 

Xiao said that while there are still improvements to be made, he believes the devices could appear on the market in five-to-ten years.