Fuel cell receives energy boost from sugar

A new enzymatic fuel cell could eventually replace conventional batteries in portable electronic devices, claim researchers who have made energy density gains with their prototype power source.

The findings from Y.H. Percival Zhang, an associate professor of biological systems engineering in Virginia Tech’s College of Agriculture and Life Sciences and the College of Engineering, have been published in Nature Communications.

While similar power sources have been developed, this one has an energy density an order of magnitude higher than others, allowing it to run longer before needing to be refueled, Zhang said in a statement. He added that the new power source could be operating inside electronic devices in as soon as three years.

‘Sugar is a perfect energy storage compound in nature,’ Zhang said. ‘So it’s only logical that we try to harness this natural power in an environmentally friendly way to produce a battery.’

The new enzymatic fuel cell forms part of Zhang’s research which has previously seen the utilisation of a series of enzymes mixed together in combinations not found in nature. Similarly, he has created edible starch from non-food plants, and developed a new way to extract hydrogen in an economical and environmentally friendly way that can be used to power vehicles.

In this latest development, Zhang and his colleagues constructed a non-natural synthetic enzymatic pathway that strip all charge potentials from the sugar to generate electricity in the enzymatic fuel cell, which uses biocatalyst enzymes in place of a platinum catalyst.

The enzymatic fuel cell combines maltodextrin, a polysaccharide made from partial hydrolysis of starch, with air to generate electricity with water as the main byproduct.

According to Zhang, nearly 24 electrons per glucose unit of maltodextrin can be produced through a synthetic catabolic pathway that comprises 13 enzymes in an air-breathing enzymatic fuel cell. Enzymatic fuel cells containing a 15 per cent (wt/v) maltodextrin solution have an energy-storage density of 596 Ah kg−1, one order of magnitude higher than that of lithium-ion batteries.

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