PORTLAND, Ore. — A superlattice electrolyte with far greater conductivity could significantly boost fuel cell efficiency while lowering costs when compared to current solid-oxide fuel cells.

Spanish researchers claim their superlattice electrolyte achieves almost 100 million times greater ionic conductivity than conventional fuel cell components. The new technique has been successfully characterized by scientists at the Energy Department's Oak Ridge National Laboratory in Tennessee.

Delphi Automotive Systems, BMW and Rolls-Royce have all announced development programs for solid-oxide fuel cells. However, fuel cells based on the new superlattice electrolyte are being touted as far more efficient and cheaper for use in automobiles.

The molecular model of the ion-conducting material explains its greater ionic conductivity by virtue of numerous vacancies at the interface between the layers in a superlattice that creates an open pathway through which many more ions can travel.

"The Spanish researchers could measure the ionic conductivity of their superlattice material, but they couldn't explain it," said Maria Varela of Oak Ridge's Materials Science and Technology Division. "Our direct images show the crystal structure that accounts for the material's conductivity. We can actually see the strained, yet ordered, interface structure and how it opens up much wider pathway for the ions.

"I can't tell you how much more efficient fuel cells using this superlattice will be, but I can tell you that they will be much cheaper to operate," she predicted.

The Spanish researchers work at two Madrid universities: Universidad Complutense and Universidad Politcnica.

Solid-oxide fuel cells require operating temperatures of over 1,000 degrees F, but the new superlattice electrolyte design offers not only greater permeability --for greater fuel cell efficiency -- but they also operate near room temperature, thereby lowering their own and eliminating the "warm-up" delay usually associated with solid-oxide fuel cells.