The Bio-Micro Fuel Cell Grand Challenge is a Sandia project to develop new compact power sources fueled by biological hosts, such as plants or animals. It could fill a need for uninterrupted autonomous power for applications where batteries are too large or too short-lived.

The bio-micro fuel cell being developed by Sandia researchers works like a battery. However, while a battery is a "closed" system—that is its lifetime is fixed by the amount of reactants packaged inside it—the bio fuel cell is an "open" system. Its fuel is supplied on a semi-continuous basis and can be renewed by changing or refilling the fuel tank. By tapping into a plant or animal, the bio-micro fuel cell seeks to incorporate a "fuel tank" that refills itself.

At the heart of the fuel cell, fuel oxidation and oxygen reduction take place at the anode and cathode, respectively. Catalysts are incorporated into the electrodes to facilitate the reactions. A proton exchange membrane (PEM) separates the oxidation and reduction reactions and allows the use of the electrons released at the anode during oxidation in an external circuit. The protons are transported through the membrane to complete the circuit inside the fuel cell. Electrons are received back again from the external circuit at the cathode, where they react with the protons and oxygen atoms to produce water.

In the case of the bio-micro fuel cell, the fuel is glucose—a common natural sugar. When a glucose molecule comes in contact with the catalyst, it splits into two, releasing two protons and two electrons. Sandia researchers are looking at different types of catalysts to harvest more protons and electrons from the by-products produced in the first oxidation reaction. In theory, researchers should be able to harvest 24 electrons from a glucose molecule by using the appropriate catalysts.

Contact:
Chris Apblett
caapble@sandia.gov
(505) 844-3497

Blake Simmons
basimmo@sandia.gov
(925) 294-2288