Written By: Kaylee Zhou

An associate professor from the Department of Mechanical Engineering at CU Boulder, Jianliang Xiao, along with his coworkers have produced a new device that can convert the body’s natural heat into electricity. The group of researchers described the device as “stretchy enough that you can wear it like a ring, a bracelet, or any other accessory that touches your skin” (University of Colorado at Boulder, 2021). This device obtains and utilizes a person’s natural heat through thermoelectric generators in order to produce electricity. Xiao voiced his motivation for creating this new invention by stating, “We want to be able to power your wearable electronics without having to include a battery” (University of Colorado at Boulder, 2021).

How it is made
The group’s invention is made from polyimine, thin thermoelectric chips, and liquid metal wires. The base of the device consists of polyimine, since it is a stretchy material, and on top of the base, they added a series of thin thermoelectric chips. To complete the product by connecting the chips together, the researchers attached liquid metal wires onto each of the chips. The purpose of utilizing polyimine as the base of the device was to make it stretchable without damaging the thermoelectric chips, which are brittle and could break easily under the wrong conditions. The polyimine is also easily mendable. The researchers emphasized that “the devices are also resilient, and if the device tears, it could be pinched back together where it would seal up in a few minutes” (McGlaun, 2021). Another benefit of the device’s materials is that they are all reusable. Xiao mentioned that when it is time to dispose of the device, it can be placed into a special solution that first dissolves the polyimine base and then separates the electronic components. The reusable components have a significant benefit on the environment because they are preventing additional amounts of waste from being contributed to the surroundings. Xiao also brought to attention that the device could easily increase the amount of electricity it produces by additional blocks of generators. He states, “What I can do is combine these [thermoelectric generators] units to get a bigger unit. It’s like putting together a bunch of small Lego pieces to make a large structure. It gives you a lot of options for customization” (United Press International, 2021).

How it works
The thermoelectric generators within the device have very close contact with the human body and skin, so they are able to utilize the body heat that would normally be discharged into the environment to generate electricity. For example, body temperatures increase during exercise, and that released heat diffuses into the surrounding air, but this new invention captures the heat that is supposed to be released and converts it to electricity so that it is not wasted. The researchers stated, “The devices can generate about one volt of energy for every square centimeter of skin space — less voltage per area than what most existing batteries provide but still enough to power electronics like watches or fitness trackers” (University of Colorado at Boulder, 2021). This device is a recent success compared to the researchers’ previous attempts in creating a product that can provide electricity. In the past, the researchers were puzzled as to how to create a device that would not need to be connected to an external power source, like a battery, in order to function. In fact, after the team’s success with this invention, Xiao stated, “The nice thing about our thermoelectric device is that you can wear it, and it provides you with constant power [without an external power source]” (University of Colorado at Boulder, 2021).

Conclusion
The researcher’s device is both a more conservative and polished alternative in comparison to current electrically-powered devices, especially since it is able to heal itself and can be fully recycled. In regard to the production of the product, Xiao has said, “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” (University of Colorado at Boulder, 2021). Confident in their product, the team hopes to see their product in regular markets in anywhere from five to ten years.

References and Sources
McGlaun, S. (2021, February 12). Cheap wearable device converts body heat into electricity. Retrieved February 21, 2021, from https://www.slashgear.com/cheap-wearable-device-converts-body-heat-into-electricity-12659187/
United Press International. (2021, February 11). New wearable device converts body heat into electricity. Retrieved February 21, 2021, from https://gephardtdaily.com/national-international/new-wearable-device-converts-body-heat-into-electricity/
University of Colorado at Boulder. (2021, February 10). New wearable device turns the body into a battery. Retrieved February 21, 2021, from https://www.sciencedaily.com/releases/2021/02/210210142049.htm