While other sugar fuel cells have been developed, this one his has an energy density an order of magnitude higher than others, said to team leader Percival Zhang leads the team: “Sugar is a perfect energy storage compound in nature. It’s only logical that we try to harness this natural power in an environmentally friendly way to produce a battery.”
According to the University, Zhang has used a series of enzymes mixed in combinations not found in nature, constructing "a non-natural synthetic enzymatic pathway that strip all charge potentials from the sugar to generate electricity. Low-cost biocatalyst enzymes are used as catalyst instead of platinum."
The fuel is maltodextrin, a polysaccharide made from partial hydrolysis of starch. “We are releasing all electron charges stored in the sugar solution slowly step-by-step by using an enzyme cascade,” Zhang said.
"Here we show that 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," said the team in the abstract of the Nature paper A high-energy-density sugar biobattery based on a synthetic enzymatic pathway.
Maximum output in the demonstrator is 0.8mW/cm2 and?mA/cm2.
Claimed current density for a enzymatic fuel cell containing a 15% maltodextrin solution is 596Ah/kg, which seems rather high, and could be the potential energy density of the solution alone.