Sony runs Walkman off sugar-based bio battery

A year ago it seemed Sony couldn't even get a laptop battery right. A massive recall of lithium-ion cells tainted its image and had the company scrambling, but on Thursday it reported a sweet breakthrough in bio battery technology.

Sony, one of the world's largest battery makers, said it had succeeded in creating a battery that produces electricity by breaking down sugar. The bio cell, which measures 39 millimeters cubed, delivers 50mW (milliWatts) -- a world record for such a cell, according to the company.

A video provided by Sony shows four of the cells connected in series delivering enough energy to power a Walkman music player. The battery uses glucose solution as a fuel. A second video shows a small fan being powered by the cell with a glucose-based sports drink used as the fuel.

As in other cells, power is produced through a flow of electrons between a cathode and anode.

In the bio cell 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.

Details of the bio battery were accepted as a paper at the 234th American Chemical Society National Meeting and Exposition that is taking place this week in Boston.

Sugar is naturally occurring so the technology could be the basis for an ecologically friendly energy source. Companies such as Sony are researching numerous technologies that could replace the dominant lithium-ion cells as a clean power source for portable electronics.

One of the most talked about is fuel cell technology. While hydrogen-based cells have taken off for home or automobile use, versions based on methanol for use in electronics products have yet to be commercialized. Toshiba and NEC are among the companies that promised methanol fuel cell-based laptops in previous years, but each time, technology launches have been delayed.