Phone chargers may become a thing of the past thanks to designs like the RevOlve concept phone. The RevOlve concept phone is a phone that charges using kinetic energy generated by spinning the phone around your finger.
The phone is designed specifically to be spun with a large hole punched out in its bottom which can also be used to attach the RevOlve to a keychain or to a carabiner. As for the phone's interface, I could see it being touchscreen, although the controls would be very cramped. I think the most important feature of this phone is that it eliminates the wall charger completely. While wall chargers aren't the Earth's biggest polluters, they are still plugged into the grid. When you add up all the millions of cellphones around the world, you'll be surprised to see how much electricity is actually being used.