Developing chromium capture technology prevents poisoning of solid oxide fuel cells | The American Ceramic Society

Developing chromium capture technology prevents poisoning of solid oxide fuel cells


[Image above] Credit: romana klee; Flickr CC BY-SA 2.0

It’s still early in the year, but my predictions of the materials science wonders to watch in 2016 are already shaping up nicely.

We’ve seen big news in additive manufacturing of ceramics (here and here) and continual improvements in alternative energy. And fuel cells, number three on the watch list, are making headlines, too.

After a solid oxide fuel cell (SOFC) broke records last year for the longest continual run, it seemed that fuel cells were well on their way to making continuous and clean energy a viable solution for a sustainable future.

But degradation is a serious problem that threatens long-term use of fuel cells—a necessity for full utility of this energy solution.

“One of the reasons that fuel cells degrade is poisoning of the cathode by chromium contaminants when incoming air flows into the fuel cell,” says Prabhakar Singh, UTC Endowed Chair Professor and director of the Center for Clean Energy Engineering at the University of Connecticut.

Chromium poisoning leads to performance degradation and compromises long-term stability of the fuel cell—bad news if you want those cells to break new records.

“Although surface coatings and bulk material chemistry modifications have been utilized to reduce the overall evaporation of chromium from the metallic components present in the cell stacks and balance of plant sub systems, the approaches add additional cost,” Singh says. Long-term stability of the coatings is also an issue, Singh says, because the coatings can form cracks and allow inter-diffusion.

So Singh and his research group are working on a solution to this chromium poisoning problem by developing a capture technique that can grab the chromium within the fuel cell, preventing it from reaching and poisoning the fuel cell cathode. The technology uses complex oxides, “formulations of which are based on thermodynamics of reaction processes,” Singh says.

The project is funded by the U.S. Department of Energy.

“We are very excited with the experimental validation of the concept in our laboratory,” Singh adds. “The team developed the concept, synthesized the materials, fabricated the device, and tested them under SOFC systems operating conditions. The device termed a ‘chromium getter’ has shown excellent chromium capture efficiency during transpiration and electrochemical tests.”

According to Singh, the chromium getter is cost-effective and will work for different SOFC system designs and beyond, such as high temperature electrochemical systems.

Singh recently presented the team’s latest findings at ICACC’16. Some of the past data, presented at the 16th Annual SOFC Worskhop in July 2015, can be accessed here.

The team has filed a U.S. patent application for the chemistry, fabrication, and SOFC application of the getters. The scientists are currently working to scale-up the fabrication process and hopes to eventually tests samples of its technology with SOFC industry partners.