Scientists in the US have developed a sugar-powered "biobattery" that they say stores 10 times more energy than the equivalent-size lithium-ion batteries found in smartphones.

According to the team at Virginia Tech university, the results of their work could be in use within three years – and recharging could be a matter simply of adding some more sugar.

"Sugar is a perfect energy-storage compound in nature," said Y H Percival Zhang, professor of biological systems engineering at Virginia Tech. "So it's only logical that we try to harness this natural power in an environmentally friendly way to produce a battery."

Their “biobattery”, which releases energy from sugar instead of chemicals such as lithium, used in batteries found in today's electronic gadgets, could replace conventional disposable or rechargeable batteries – and is cheaper, refillable, biodegradable and more environmentally friendly.

The researchers reported their work in the latest issue of Nature Communications.

The new battery technology produces significantly more energy from the sugar fuel than ever before. It can also store “one order of magnitude” - 10 times - more energy than the lithium-ion batteries commonly used in portable electronics and electric cars, claim the researchers. That could greatly extend the battery life of smartphones, tablets, and electric cars.

From potatoes to batteries

The battery operates like other types of fuel cell, breaking down a fuel and releasing energy in the process. It is powered by a partially digested starch – the foodstuff present in high-energy plant-based foods such as potatoes that are broken down into sugar in the gut. 

The starch is broken down into a complex sugar called maltodextrin (already available as a food additive), which is then further broken down by a chain of 13 enzymes. The process releases significant qualities of electrons - which can be used to generate a current, which can in turn power electronic devices. The main byproduct is water being its main byproduct, making it environmentally friendly.

"We are releasing all electron charges stored in the sugar solution slowly step-by-step by using an enzyme cascade," said Zhang.

Unlike other fuel cell technologies, including hydrogen and methanol fuel cells, the sugar solution used in the new biobattery is neither explosive nor flammable, making it an ideal candidate for powering portable gadgets that often sit in pockets or bags.

Zhang and his team claims that in "as soon as three years", the new battery could be fitted to and run some of the myriad of electronic gadgets including mobile phones, tablets and portable video games, and could be cheaply refilled like an ink cartridge.

http://www.theguardian.com/technology/2014/jan/22/sugar-battery-green-powered-gadgets-three-years