SiEnergy Lowers Solid-Oxide Fuel Cell Temperature by 300-500 °C

April 26th, 2011 by Nicholas Brown

What is a fuel cell?

A fuel cell stack is a solid-state (no moving parts) fuel-powered electricity generator, which also generates heat. It can be used to supply electricity to homes, businesses, electric vehicle motors, electric vehicle chargers, and whatever else requires electricity. Fuel cells are meant to be direct replacements for fossil-fueled combustion-engine-powered generators (gasoline-powered generators, natural gas generators, propane generators, etc).

Solid-oxide fuels cells can be fueled by natural gas, diesel, and other fuels.

Traditionally, solid-oxide fuel cell generators operate at a temperature of 800-1,000 °C, but SiEnergy has discovered that, using thin-film electrolytes that are mechanically supported my a metal grid, it is feasible to construct significantly larger versions of previous thin-film electrolyte designs. The metal grid is deposited on top of the 100-nanometre-thick electrolyte membrane, which is made of yttrium and zirconia during heating and cooling in the construction process. Thin-film solid-oxide fuel cells can operate at lower temperatures than traditional ones. The thin-film electrolytes expand and contract during the heating and cooling process and will tear too easily, which is why they were traditionally limited to a very small scale.

The mechanically supporting metal grid mentioned above is also being used as the anode because it is electrically conductive. The cathode intakes oxygen from the air, reduces it, and the resulting oxygen ions are transferred through an electrolyte membrane to the anode to oxidize the fuel.

Harry Tuller from MIT said: “The challenge has been that the films, being so thin, are fragile and easily tear during processing or during heating and cooling cycles.” Traditionally, operating temperatures for solid oxide fuel cells had to be high because of the fact that the ions traveled quickly enough only at high temperatures.

SiEnergy has demonstrated fuel cell arrays of about 5 mm squared. Shriram Ramanthan, a professor of materials science at Harvard, said that they can be scaled up to centimetre scale. The company hopes to offer systems as replacements for residential diesel electricity generation and heating systems.

via Technology Review

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Tags: Electricity, Electrolyte, Energy, Fuel Cells, solid oxide fuel cell

About the Author

Nicholas Brown writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is: Kompulsa.com.