The NoPoPo (which stands for no pollution power) batteries get their juice from your juice. You don't have to pee on the battery. Just into a cup, then suck it up with a pipette, then inject it into the battery. They make it sound so easy and not gross.
But if you're not the peeing into pipettes type, you can also use water, beer, saliva, apple juice or coco-cola. A mixture of magnesium and carbon reacts with the liquid and produces power up to 500 mAh in the case of an AA-size battery. The batteries come in AA and AAA and retain their charge for up to 10 years, but they can only be recharged two to five times, on average.