Well, my cousin wanted me to help him to build a potato radio as a school project. His teacher suggested him to make one and said him that a potato is one thing more than a battery! He told him that a potato is a capacitor, resistor and even a diode!
I do know what a potato Battery is. I remember that have seen a potato Defibrillator capacitor some where too.
But it seems the teacher wanted something more than a radio, powered by a potato. He wanted an edible radio!! lol