There are very small batteries that use the changes in its environments, but it use in general vibration, or light, or sugar (see https://en.wikipedia.org/wiki/

There are very small batteries that use the changes in its environments, but it use in general vibration, or light, or sugar (see https://en.wikipedia.org/wiki/Sugar_battery https://en.wikipedia.org/wiki/Sugar_battery). But the power is very small, used for very low power devices. One could think to use the sun cycle (become a little bit warm, then a little bit colder during the night), but at this point solar panel do the trick.