Power supply is often one of the biggest hurdles for IoT devices. Researchers at North Carolina State University (USA) have developed a thermoelectric generator that can provide enough power for wearable electronic devices. The prototypes are extremely lightweight and easily adapt to the shape of the user’s body.

A wearable thermoelectric generator exploits the temperature difference between the user’s body and the surroundings to generate electricity. Previous versions could only supply a few microwatts per square centimeter, or they used relatively large, stiff heat sinks. The new technology can generate up to 20 µW per square centimeter and does not need a heat sink, making it light and comfortable.

The new design has a layer of thermally conductive material next to the user’s body that absorbs heat from the body. It is covered by a polymer layer that prevents dissipation of the heat into the surrounding air. The absorbed heat is fed to a centrally located thermoelectric generator with an areas of 1 square centimeter, where it is converted into electricity. Residual heat is quickly dissipated to the air through a second thermally conductive layer. The entire arrangement is just 2 mm thick and is very flexible.