Thermoelectric systems are based on technology that leverages differences in temperature to generate electricity, and we’ve seen how this approach can be applied to the world’s tiniest refrigerator, cooking pots that power smartphones and even thermoelectric paint. A new example from scientists at the University of Colorado (UC) explores the everyday potential of this technology, demonstrated as a ring that harvests energy from the human body and can even repair itself when damaged.
The thermoelectric ring is an extension of earlier research from the group of UC mechanical engineers, who in 2018 demonstrated a type of electronic skin that could bend, twist, and conform to the actual skin of its wearer. Embedded with sensors, the skin was designed to function as a discreet wearable computer, but perhaps its coolest function was that it could heal itself when damaged.
This was due to the structure of the e-skin, which consisted of a special polymer called polyimine that was doped with silver nanoparticles, creating a chemical bond that could mend itself in the event of a tear. This attribute is again a key feature of the team’s newest device, though unlike the e-skin, the thermoelectric ring doesn’t need to be hooked up to an external power source.
Instead, it “turns the body into a battery,” tapping into the difference between a wearer’s natural body heat and ambient air, using thermoelectric generators to convert that into electricity. These consist of tiny thermoelectric chips planted onto a polyimine base, which are then connected with liquid metal wires. This device can generate one volt for every square centimeter of skin it covers, which the researchers say is enough to power electronics like watches and fitness trackers.
Conveniently, the team says sets of these generators can simply be joined together to up the power output in a process likened to putting together pieces of Lego. The scientists calculate that a version scaled up to the size of a wristband could generate around 5 volts. Additionally, the device is fully recyclable, with all its components able to be dissolved or separated for reuse via submersion in a special solution.
“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,” says Jianliang Xiao, senior author of the paper.
The research was published in the journal Science Advances, while the video below provides an overview of the technology.
Source: University of Colorado