A robust fuel cell that runs on methane at practical temperatures

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FUEL CELLS have not been particularly known for their practicality and affordability, but that may have just changed. There’s a new cell that runs on cheap fuel at temperatures
comparable to automobile engines and which slashes materials costs.

Though the cell is in the lab, it has high potential to someday electrically power homes and perhaps cars, say the researchers at the Georgia Institute of Technology who led its development. In a new study in the journal Nature Energy the researchers detailed how they reimagined the entire fuel cell with the help of a newly invented fuel catalyst.

The catalyst has dispensed with high-priced hydrogen fuel by making its own out of cheap, readily available methane. And improvements throughout the cell cooled the seething operating temperatures that are customary in methane fuel cells dramatically, a striking engineering accomplishment.

Methane fuel cells usually require temperatures of 750 to 1,000 degrees Celsius to run. This new one needs only about 500, which is even a notch cooler than automobile
combustion engines, which run at around 600 degrees Celsius.

That lower temperature could trigger cascading cost savings in the ancillary technology needed to operate a fuel cell, potentially pushing the new cell to commercial viability.
The researchers feel confident that engineers can design electric power units around this fuel cell with reasonable effort, something that has eluded previous methane fuel cells.

“Our cell could make for a straightforward, robust overall system that uses cheap stainless steel to make interconnectors,” said Meilin Liu, who led the study and is a Regents’
Professor in Georgia Tech’s School of Material Science and Engineering. Interconnectors are parts that help bring together many fuel cells into a stack, or functional unit.

“Above 750 degrees Celsius, no metal would withstand the temperature without oxidation, so you’d have a lot of trouble getting materials, and they would be extremely expensive and fragile, and contaminate the cell,” Liu said.

“Lowering the temperature to 500 degrees Celsius is a sensation in ourworld. Very few people have even tried it,” said Ben deGlee, a graduate research assistant in Liu’s lab and
one of the first authors of the study.

“When you get that low, it makes the job of the engineer designing the stack and connected technologies much easier.” The new cell also eliminates the need for a major ancillary device called a steam reformer, which is normally needed to convert methane and water into hydrogen fuel.

Liu, deGlee, co-first author Yu Chen, the results of their research on October 29, 2018. Their work was funded by the Office of Basic Energy Sciences and the Advanced
Research Projects Agency-Energy (ARPA-E), both in the U.S Department of Energy. It was also funded by the National Science Foundation’s Division of Chemistry.