As body-worn and implanted medical devices proliferate, the need to use power from something other than batteries increases. Researchers from Huazhong University of Science & Technology developed a wearable flexible device that can generate electricity from body heat.
The device relies on two gel electrolytes, allowing the final device to be flexible and produce as much as 0.7 volts and 0.3 µW. Since the system works using the thermogalvanic effect, the higher the difference between the body temperature and the environment, the greater the voltage. While above numbers are pretty impressive and sufficient to power a lot of potential devices, they were produced when the environment was only 5°C above freezing, way too cold for most applications.
Read more about this study and technology here.