Abstract
The performance and degradation of Solid Oxide Fuel Cells (SOFC) were studied under severe operating conditions. The cells studied were manufactured in a small series by ECN, in the framework of the EU funded COREโSOFC project. The cells were of the anodeโsupported type with a double layer LSM cathode. They were operated at 750โยฐC or 850โยฐC in hydrogen with 5% or 50% water at current densities ranging from 0.25โAโcm^โ2^ to 1โAโcm^โ2^ for periods of 300โhours or more. The area specific cell resistance, corrected for fuel utilisation, ranged between 0.20โฮฉโcm^2^ and 0.34โฮฉโcm^2^ at 850โยฐC and 520โmV, and between 0.51โฮฉโcm^2^ and 0.92โฮฉโcm^2^ at 750โยฐC and 520โmV.
The degradation of cell performance was found to be low (ranging from 0 to 8%/1,000โhours) at regular operating conditions. Voltage degradation rates of 20 to 40%/1,000โhours were observed under severe operating conditions, depending on the test conditions.
Data analysis revealed a critical cell voltage of ca 750โmV, above which the degradation rates were trivial, but below which they were significant.
Some cells were also tested using a different procedure to that usually applied at Risรธ. This gave a different aging behaviour, indicating that the detailed test circumstances may be decisive to the outcome.