Saturday, August 22, 2009

Key among

Key among these advantages is the ability to run on readily available fuels, such as methanol or even gasoline, which contain hydrogen bound to carbon and sometimes oxygen. The other five types of fuel cell can do this as well, but only with the help of additional hardware called a "reformer," which extracts pure hydrogen from these other fuels. These reformers cost extra money, add bulk to the engine, and sap power, cutting the engine's overall efficiency roughly in half.
Solid-oxide fuel cells are able to consume methanol-like fuels without reformers.
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Most of the environmental benefit of fuel cells is lost when hydrocarbon fuels are used, because extracting hydrogen from them leaves behind CO2 and pollutant gases that end up in the exhaust. But it helps solve the "chicken and egg" problem: Who's going to buy hydrogen-powered cars until most gas stations have hydrogen pumps? But what company is going to pay to install hydrogen pumps at hundreds of gas stations until there are plenty of fuel-cell cars on the road? Solid-oxide fuel cells can bridge the gap. They can run on methanol or gasoline now and then switch to pure hydrogen as it becomes available.
Image copyright Powertech Labs. more
Hydrogen fuelling stations like this one in Vancouver, Canada, are still rare. The vehicle fuelling up is a Ford FCV.
The thin-film variety being developed at TcSAM improves on this fuelling flexibility. Ignatiev explains: "Normal solid-oxide fuel cells can use fuels like methanol, but they become impaired over time as carbon coats the fuel cell's nickel electrode," he says. "This happens partly because of the cell's 1,000-degree operating temperature. Research shows that this doesn't happen - at least not to an appreciable degree - at the lower temperatures at which our cells operate."
TcSAM's fuel cells have not yet been tested with fuels other than pure hydrogen, Ignatiev says, but the scientists plan to perform tests with methanol-like fuels during the next stage of research.
There's still much work to be done. If all goes well, though, these thin films could pave the way to clean-running SUV's and other wonders of a hydrogen-based economy.

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