Scientists develop biodegradable fuel cell that runs on sugar and has higher energy density than lithium ion batteries

A very exciting bit of news for those of us who track the rapid developments in the bioeconomy: researchers at Saint Louis University in the U.S. have developed a fuel cell battery that runs on virtually any sugar source - from soft drinks to tree sap - and has the potential to operate three to four times longer on a single charge than conventional lithium ion batteries.

For consumers, the 'biobattery' could mean significantly longer time to talk and play music on their iPods, cell phones and laptops. For the world's farmers, this means the carbohydrate economy gets another boost. Our post-petroleum economy is becoming an ever sweeter one...

Like other biofuel cells, the sugar battery contains enzymes that convert fuel - in this case, sugar - into electricity, leaving behind water as a main byproduct. But unlike other fuel cells, all of the materials used to build the sugar battery are biodegradable. This gives it a huge advantage over the millions of common batteries used in electronics, which are becoming a big waste problem.

The new battery could eventually replace lithium ion batteries in many portable electronic applications, including computers, the scientists say. Their findings were described today at the 233rd national meeting of the American Chemical Society in Chicago.

"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," said study leader Shelley Minteer, Ph.D., an electrochemist at Saint Louis University (picture). "It demonstrates that by bridging biology and chemistry, we can build a better battery that's also cleaner for the environment."

Using sugar for fuel is not a new concept: sugar in the form of glucose supplies the energy needs of all living things. While nature has figured out how to harness this energy efficiently, scientists only recently have learned how to unleash the energy-dense power of sugar to produce electricity, Minteer said.

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. As proof of concept, she has used a small prototype of the battery (about the size of a postage stamp) to successfully run a handheld calculator. 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:
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Consumers aren't the only ones who stand to benefit from this new technology. The military is interested in using the sugar battery to charge portable electronic equipment on the battlefield and in emergency situations where access to electricity is limited. These devices include remote sensors for detecting biological and chemical weapons. Devices could be instantly recharged by adding virtually any convenient sugar source, including plant sap, Minteer said.

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.

One of the first applications Minteer envisions for the sugar fuel cell is using it as a portable cell phone recharger, similar to the quick rechargers already on the market that allow users to instantly charge their cell phones while 'on the go.' Ideally, these rechargers would contain special cartridges that are pre-filled with a sugar solution.

These cartridges then could be replaced when they're used up. Ultimately, she hopes that the sugar battery can be used as a stand-alone battery replacement in a wide range of portable electronic devices.

Future work includes modifying the battery's performance for varying environmental conditions, including high temperatures, and extending the life of the battery, Minteer said. Funding for this study was provided by the U.S. Department of Defense.

A chemistry professor at Saint Louis University, Minteer already has invented a biobattery than can run on alcohol and natural enzymes. She formed a start-up company with a former graduate student to develop commercial applications for the invention. The company has secured millions of dollars in venture capital and other investments.

The Saint Louis University scientist says her long-term goal is to create a rechargeable battery that not only lasts longer, but also is also friendly to the environment.

For her groundbreaking research, Minteer earned the 2005 Innovation Award from the Academy of Science of St. Louis. From freshmen to graduate assistants, Saint Louis University students at all levels work in her lab.