New fuel-cell battery technology developed by Sony delivers electricity from sugar drinks.

Japanese entertainment giant Sony has had a fairly forgettable 12 months in its Lithium-ion battery division with the recall of millions of notebook batteries from computer vendors around the world.

However, the company could well be looking forward to a sweeter future, having unveiled its new “bio battery” that runs from sugar.

The new fuel-cell technology based design breaks free from the traditional energy sources of Methanol and instead uses enzymes to break down or oxidise the sugar and create electrical energy.

The experimental cell shown off by the company at the latest meeting of the American Chemical Society generates 0.3VDC and 5mA of current per square centimetre for an output power of 1.5mW/cm2. Sony rates the open-circuit voltage of the cell at 0.8V.

The company has claimed the world record output from a biological battery of this type at 50mW with its 39mm cubed prototype.

By stringing four of these cells in series, enough power was developed to run a flash memory based MP3 Network Walkman player in demonstrations.

The company outlined four main areas of research it is looking into with development of its bio-battery technology – improving the efficiency of the electron transportation from the enzymes; improving the efficiency of the electrode structure to offer better oxidisation and therefore, more electrons; improved electrolyte efficiency to aid in generation of more electrons; reducing the size of the bio-battery and improving power to weight ratio.

The announcement follows developments from St Louis University in March 2007 where researchers announced they had developed a fuel cell that ran from any sugar source from soft drink to tree sap.

Fuel cells have been considered one of the major advances to come in battery technology in the last 15 years as the demand for power in portable devices continues unabated.

So far, fuel cell technology based on methanol has failed to meet the original hype of notebook computers running for 15 hours and the like that were being spouted a year or two ago. It’s also likely that bio-batteries such as the St Louis University and Sony announcements will be some years away from commercial reality. In fact, Sony sensibly makes no pronouncements about when bio batteries will be a practical reality.

However, both Sony and St Louis University are upbeat about the possibilities of bio-batteries with the latter expecting bio-cells to overtake Lithium-ion technology.

"This study shows that renewable fuels can be directly employed in batteries at room temperature to lead to more energy-efficient battery technology than metal-based approaches," said study leader Shelley Minteer, Ph.D., an electrochemist at Saint Louis University. "It demonstrates that by bridging biology and chemistry, we can build a better battery that's also cleaner for the environment."

The chemical process used by Sony sees enzymes break down the glucose molecules into gluconolactone with two hydrogen ions (H+) and two free electrons. Cellophane is used as the separation device that channels the electrons.

The process used here is described as “passive” and utilises oxygen from the atmosphere to start and continue the process.