Striving to decreased operating temperature of Solid Oxide Fuel Cells
According to a Professor Eric Wachsman from the University of Maryland, the lack of funding for fuel cell research is putting the country at risk of falling behind in the development and implementation of the most efficient means of converting fuel to electricity. Fuel cells have up to three times the efficiency of an internal combustion engine and some variations are easily produced at low costs.
“There is a problem in the perception of the public and policy makers, and in the funding of our fuel cell programs, that hydrogen and fuel cells are linked”, said Wachsman, director of the University of Maryland Energy Research Center (UMERC). “Hydrogen-based fuel cells are the technology that has gotten all of the press and as a result we’re still waiting for a future hydrogen infrastructure. Yes, fuel cells can run off hydrogen, but they don’t have to.”
Unlike the proton exchange membrane (PEM) fuel cells which rely on hydrogen to generate power, the solid oxide fuel cells (SOFCs) are capable to oxidize any kind of fuel. Although SOFCs can be powered by gasoline, diesel and natural gas, as well as biofuels and hydrogen, they aren’t capable to operate on temperatures that PEM fuel cells are able to.
While PEM fuel cells operate at around 80°C (180°F), currently available SOFCs operate at 800°C (1500°F). In order to make SOFC more practicable, Wachsman and his colleagues recently developed a SOFC capable to generate 2 watts of power per square centimeter at 650°C (1200°F).
The cell uses a bi-layer electrolyte developed by Wachsman that is more than 100 times more conductive than the conventional zirconia-based electrolyte operating at the same temperature. When the cells are assembled into a stack they should produce three kilowatts of electricity per kilogram of material – making it as efficient as an internal combustion engine at approximately one-third of its size.
The team plans to further lower operation temperature by making improvements in the SOFC electrolytes and nanostructured-electrode designs, and they believe it could be as low as 350°C (660°F). That breakthrough would enable SOFC use in automotive industry, but it would also lower its price because they could be manufactured from less expensive materials.
Wachsman claims it will take decades to create a hydrogen distribution and storage system, and to convert every gas station into a hydrogen filling station just in the States. He might be wrong if we witness advances in water treatment technologies used to produce hydrogen, or more efficient ways to harvest or produce hydrogen. SOFC are already used for other applications, and one good example is Bloom Box fuel cell system used by many major companies, but it isn’t usable in vehicles where PEM fuel cells have a significant advantage due to their much lower operating temperature.
For more information, read the paper published in journal Science named: “Lowering the Temperature of Solid Oxide Fuel Cells“.
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