Regenerative fuel cell

Developed for stationary or mobile applications requiring power levels greater than 1 kW, a zinc/air fuel cell produces electrical energy by the same electrochemical processes that occur in primary zinc/air batteries. In contrast to being discarded like a primary battery, slowly recharged like a secondary battery, or rebuilt like a "mechanically recharged" battery, a zinc/air fuel cell can be conveniently refueled in minutes or seconds.

Zinc "fuel," in the form of pellets about 1 mm in diameter, is consumed and releases electrons to drive a load (the anodic part of the electrochemical process). Oxygen from ambient air accepts electrons from the load (the cathodic part). The overall chemical reaction produces zinc oxide (ZnO), a non-toxic white powder. When all or part of the zinc has been consumed, removing the reaction product and adding fresh zinc pellets and electrolyte refuels the cell. The ZnO product is reprocessed into zinc pellets and oxygen in a separate recycling unit using electrolysis.

The technology is expected to displace lead-acid batteries where higher specific energy or very rapid recharges are valuable, and internal combustion engines where zero emissions, quiet operation, or lower maintenance costs are important.

Steve Schaefer, Metallic Power, 2320 Camino Vida Roble, Carlsbad, CA 92009; Tel: (760) 476-8000; Fax: (760) 476-8080; E-mail: [email protected]. For more information, Enter 509

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