: Modern TEGs can power small electronics like smartwatches (e.g., MATRIX PowerWatch) and fitness trackers without ever needing a battery [6, 18].
Engineers are developing —thin, flexible materials that convert the temperature difference between your skin and the air into electricity [3, 15]. Body Heat
While this heat is essential for life, it is also a form of "waste" energy that scientists are now learning to harvest. The Biology: How We Generate Heat : Modern TEGs can power small electronics like