Researchers at St. Louis University in Missouri have developed a fuel cell which can produce electricity from sugar. It has been tested with a glucose solution, carbonated soft drinks and even tree sap.



The research was funded by the Department of Defence, which is interested in developing technology to enable the charging of portable electronic devices in battlefield or emergency situations where electricity is not readily available.

The researchers have suggested that the fuel cell could be used to replace lithium-ion batteries in electronics such as computers and mobile phones. They currently have a cell the size of a postage stamp which can power a handheld calculator.

Fuel cells work differently than electrochemical cells widely used in conventional batteries. Batteries generate electricity from a closed system, whereas fuel cells consume the fuel source, which must be constantly replaced. The researchers designed a fuel cell which consumes sugar and replaces it with byproducts, mainly water.

Other researchers at Arizona State University in Temple have created a hydrogen-gas generator they believe can be developed into a fuel cell, which could replace common batteries, offering three to five times longer life than a traditional battery of exactly the same size.

The generator uses a special borohydride solution which has a high capacity for storing hydrogen, which is used to create electricity. It is possible to package the fuel cell exactly the same as conventional batteries, and is recharged by refilling a cartridge.

One of the main problems in developing hydrogen fuel cells has been finding hydrogen-rich compounds to be used as a fuel source. Gasoline, methanol, ethanol and vegetable oil have all been looked into. Borohydride has shown recent promise as a safe, hydrogen storage compound. Unlike the others, it does not require high temperatures to work.

Other materials are added to the botohydride to increase the storage by two or three times, and also stop the solution from solidifying, which can potentially clog or damage the fuel cell.

Hydrogen fuel cells have been a popular area of alternative energy research, but technical problems have continued to jeopardise their practicality.

Hydrogen powered cars are yet to be widely commercially available despite years of research and impressive claims by car manufacturers.