Sony yesterday announced it had succeeded in creating environmentally-friendly prototype battery that produces electricity solely through the chemical reactions of sugar. The bio cell, which measures 39 millimeters cubed, achieved an output of 50 milliwatts, enough to play music on a Walkman, Sony said.

Sugar-digesting enzymes at the anode extract electrons and hydrogen ions from the glucose. The hydrogen ions pass through a membrane separator to the cathode where they absorb oxygen from the air to produce water as a byproduct. The electrons flow around the circuit outside the device producing the electricity needed to power it.
Interestingly, the new method doesn't require sugar or other largely pure sources of glucose to work, as it was demonstrated yesterday when a Sony employee poured a sugary sports drink to power a music player and a pair of speakers.

Development is still early for the battery, but the company believes the technology could be the basis for an ecologically-friendly energy source that could potentially replace lithium-ion batteries or fuel cells in the future. Sony said it would continue to develop the prototype and study ways to put it into practical use.