Finding alternative sources of energy is one of the latest challenges in science and technology and each company involved in electronics is testing different options.

For example, the Japanese company Sony is developing a bio battery that generates electricity from carbohydrates (sugar) utilizing enzymes as its catalyst, through the application of power generation principles found in living organisms.

According to Sony, test cells of this bio battery have achieved power output of 50 mW, which is sufficient to power music play back on a memory-type Walkman together with a pair of passive-type speakers (no external power source).

The concept behind the bio battery is simple, but ingenious. Sony developed a system of breaking down sugar to generate electricity that involves efficiently immobilizing enzymes and the mediator (electronic conduction materials) while retaining the activity of the enzymes at the anode. Sony also developed a new cathode structure which efficiently supplies oxygen to the electrode while ensuring that the appropriate water content is maintained.

"Sugar is a naturally occurring energy source produced by plants through  photosynthesis," Sony said in a statement.

"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 bio battery does not require mixing, or the convection of glucose solution or air; as it is a passive-type battery, it works simply by supplying sugar solution into the battery unit. The cubic (39 mm along each edge) cell produces 50 mW, representing the world's highest power output among passive-type bio batteries of comparable volume. The bio battery casing is made of vegetable-based plastic (polylactate).

The Japanese company said that it intends to produce the batteries for commercial use, but a possible timeframe wasn’t announced.

Last year, Dell, Apple, Toshiba and Lenovo recalled over 8 millions lithium-ion batteries manufactured by Sony, after incidents reported by customers.

Earlier this month the researchers at Rensselaer Polytechnic Institute have announced that  they developed a new energy storage device which resembles to a simple sheet of black paper, not only because how it looks, but also due to its weight and flexibility.

The nanoengineered battery can also be rolled, twisted, folded, or cut into any number of shapes with no loss of mechanical integrity or efficiency. The paper batteries can be stacked, like a ream of printer paper, to boost the total power output and the researchers’ deepest ambition is to produce one day enough reams of paper to power a car.