Army studies biofuel cells for sensors

The Army is investigating whether a new type of fuel cell that uses biologically active enzymes as a catalyst could provide a longer-lasting power source for unattended ground sensors.

Akermin, based in St. Louis, has signed a one-year, $1 million contract with the Army’s Communications- Electronics Research, Development and Engineering Center (CERDEC) to refine the design of the company’s Stabilized Enzyme Biofuel Cells (SEBC) and show they are suitable for military applications. The cells do not contain live organisms but use enzymes similar to those found in living cells to trigger the oxidation of ethanol fuel and generate electricity. Most fuel cells use precious metals as a catalyst, making them more expensive to manufacture and more toxic to dispose of.

Although current SEBC designs aren’t suitable for high-power applications, Akermin officials say the fuel cells will last longer than traditional ones for low-power, long-term applications. In addition, the cells and their power supply should fit in about half the space of the batteries that would be required for the same purpose.

CERDEC officials say that in the near term, the fuel cells would most likely be used to power border or perimeter sensors that are left in place for an extended time to monitor disturbances such as tremors, chemical agents or radiation.

If it proves to be adaptable, the technology could also be a lighter, more compact replacement for the batteries in some of the equipment soldiers carry, said Elizabeth Ferry, leader of the fuel cell technology team at CERDEC.

"The idea for biofuel cells has been around for about 100 years, but the problem has been that the catalyst lifetime has typically been reported as a matter of hours to days before the catalyst breaks down and becomes completely ineffective,” said Nick Akers, Akermin’s director of business development.

SEBCs, which he helped invent while a student at St. Louis University, have a polymer coating over the enzyme that allows the catalyst to last longer – as long as three and a half years in the laboratory.

Akermin’s challenge now is to create a rugged version of the technology that can withstand the extremes of temperature, vibration and other environmental conditions likely to be found in the field.

The company is also developing commercial versions of the technology, which Akers said are likely to reach the market first, given the rigorous nature of meeting military specifications.

He said he is excited by the possibility that his technology could save lives by reducing the need for warfighters to change batteries while on a battlefield.

"The other day, I actually met a Marine who said it was one of his jobs in Afghanistan to go out and change the batteries on these things,” Akers said. “And he said it was not the best thing in the world to have to do.”

About the Author

David F. Carr is a special contributor to Defense Systems.

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