Here is a new battery that is literally powered by sweat! With this battery stuck to your arm, it could be charging your phone while you work out, go hiking or do other physical activities.
The new battery is powered by lactate, which is present in human perspiration. It has a very low output right now and is in the “proof of concept” stage, but they’re working on increasing this.
“At the moment the power is not that high – only four microwatts. But we are working on enhancing it so it can power small electronic devices.”
Read more about it: http://www.bbc.com/news/science-environment-28791496