avzombie.com

Sony has developed a battery derived from sugar that has a power output of 50 milliwatts, which the company says is powerful enough to drive an MP3 player. The large green power cell is encased in vegetable-based plastic. It works by breaking down a sugar solution with enzymes to generate electricity.
Says Sony: “Sugar is a naturally occurring energy source produced by plants through photosynthesis. It is therefore regenerative, and can be found in most areas of the earth, underlining the potential for sugar-based batteries as an ecologically-friendly energy device of the future.”
The company has given no indication when commercial production might begin.