Cleveland--Fuel cells generate electricity from fuels more efficiently and with fewer emissions per watt than burning fossil fuels. But as fuel cells age, their efficiency decreases.
Researchers at Case Western Reserve University received an $800,000 Department of Energy grant to study how to make one type of fuel cell--solid oxide fuel cells--last longer.
"Loss of performance over time is holding back the technology," said Mark De Guire, associate professor of materials science and engineering at Case School of Engineering and project director. "If you're only putting out 60 percent power after five years and generating the same level of emissions, you lose advantages over conventional power technologies."
For the new research, the Department of Energy has revised the target. Industrial teams have made strides toward meeting an older target, limiting the loss of output to 1 percent per 1,000 hours of operation. The Department of Energy is now seeking just a 0.2 percent loss of output per 1,000 hours.
Solid oxide fuel cells operate at high temperatures (750 to 900 °C) and use a ceramic electrolyte, a ceramic cathode and a nickel-based cermet anode to produce electricity from fuels. To speed the search for why fuel cell performance decreases over time, an accelerated testing technique will be used in this research that replicates 5,000 hours of use in roughly one-tenth the time.
De Guire and Arthur Heuer, Distinguished University Professor and Kyocera Professor of Ceramics, will test small lab-scale fuel cells. The research will compare the performance of cells that have undergone accelerated ageing to cells that have undergone up to 500 hours of use under normal conditions.
In earlier work, the researchers found structural and chemical changes at the cathode, made of lanthanum, strontium and manganese oxides, that they suspect are likely culprits in performance loss. Other parts of the cell also degrade, but after years of operation, losses of efficiency and output are greatest at the cathode.
De Guire and Heuer will lead the analysis of microstructural and nanoscale chemical changes in the cathode materials and the cathode's interface with the ceramic electrolyte. They'll try to determine which changes cause the losses and how to prevent or reduce the impact of the changes.
The grant was awarded by the Department of Energy's Solid State Energy Conversion Alliance, a collaboration between the federal government, private industry, academic institutions and national laboratories devoted to the development of low-cost, modular and fuel-flexible solid oxide fuel cell technology.