Researchers at Saint Louis University have developed a biodegradable bio fuel cell that runs on virtually any sugar source and has the potential to operate three to four times longer on a single fill than conventional lithium ion batteries. They described their findings at the 233rd national meeting of the American Chemical Society.
Dr. Shelley Minter, an electrochemist at Saint Louis University, has been working on bio fuel cells for a number of years using a variety of different fuels, from alcohol to soybean oil. At the 229th national meeting of the ACS in 2005, she reported on fructose-based bioanodes developed by immobilizing fructose dehydrogenase in a tetrabutylammonium bromide treated Nafion membrane.
The current research details the development of a hydrophobically modified chitosan membrane which can be used as the enzyme immobilization membrane. Chitosan is a polysaccharide produced from chitin, the structural element in the exoskeleton of crustaceans.
The researchers prepared bioanodes using poly(methylene) green and Azure C as the mediators, and found that the bioanodes remained stable for more than a month and produced a maximum power density of 5.82 x 10-5 Watt/cm2 for a poly(methylene) green mediated bioanode and 4.38 x 10-5 Watt/cm2 for an Azure C mediated bioanode.
This study shows that renewable fuels can be directly employed in batteries at room temperature to lead to more energy-efficient battery technology than metal-based approaches. It demonstrates that by bridging biology and chemistry, we can build a better battery that's also cleaner for the environment.—Shelley Minteer
A few other researchers also have developed fuel cell batteries that run on sugar, but Minteer claims that her version is the longest-lasting and most powerful of its type to date. If the battery continues to show promise during further testing and refinement, it could be ready for commercialization in three to five years, she estimates.
Minteer believes that the bio fuel cell could eventually replace lithium ion batteries in many portable electronic applications, including computers.
So far, Minteer has run the batteries on glucose, flat sodas, sweetened drink mixes and tree sap, with promising results. She also tested carbonated beverages, but carbonation appears to weaken the fuel cell. The best fuel source tested so far is ordinary table sugar (sucrose) dissolved in water, she said.
Future work includes modifying the battery’s performance for varying environmental conditions, including high temperatures, and extending the life of the battery. Funding for this study was provided by the US Department of Defense.
Minteer has also formed a company to commercialize her earlier work with alcohol-fueled, enzyme-based bio fuel cells.
(A hat-tip to Ron!)
ACS 233 POLY 013: “Toward the development of an azure C mediated chitosan membrane based bioanode”