Researchers at Northwestern University studied characteristics of the electrolye material BZCYYb4411 in order to develop a more efficient fuel cell in the intermediate temperature range. Image credit: Sossina Haile et. al.

Most fuel cells operate in conditions so hot or so cold that it is difficult to build them at a reasonable commercial price. They’re a desirable product as more auto and energy companies look into shifting away from burning fuel to storing energy.

Researchers at Northwestern University have published details of a new type of fuel cell made using the double-perovskite cathode PBSCF.

It is widely agreed upon that 500°C is the paramount temperature for getting fuel cells to work, said researcher Sossina Haile. She and her team at Northwestern demonstrated outstanding power densities and long-term stability at this intermediate temperature. Specifically, these researchers found a way to combine a high-activity cathode – the double-perovskite cathode PBSCF – with a chemically stable electrolyte, labeled BZCYYb4411. This electrolyte allows ions to move quickly and remain stable for hundreds of hours.

"We solved multiple problems simultaneously by changing out the electrode, improving the electrolyte and creating good contact and communication between the two materials," said Haile.

In September 2015 a group of researchers from the Colorado School of Mines reported that they had produced an intermediate temperature fuel cell capable of producing 455 mW/cm2. Another group from the Korea Institute of Science and Technology stated that they got a similar result in 2016 at the ideal operating temperature of 500°C.

Idaho National Laboratory researchers have figured out a new fuel cell design that allows the fuel cell to utilize about three times as much carbon as earlier direct carbon fuel cell (DCFC) designs. Furthermore, because DCFCs make use of readily available fuels, they are potentially more efficient than conventional hydrogen fuel cells and can operate at under 600°C.