DEGRADATION PHENOMENA IN THE CATHODE OF A SOLID OXIDE FUEL-CELL WITH AN ALLOY SEPARATOR

A study is made of the cathode degradation phenomena in a solid oxide fuel cell that uses an alloy separator. Under the action of the discharge current, chromium diffuses from the alloy to the cathode and moves to the cathode/electrolyte interface. The cathode polarization increases in correlation with the intensity of chromium at the cathode/electrolyte interface. The increase in cathode polarization by the discharge current is due to chromium filling the pores at the cathode/electrolyte interface. This restricts diffusion of oxygen gas and decreases the number of electrode reaction sites. Chromium displacement at the cathode/electrolyte interface appears to be caused by the decrease in oxygen activity at the cathode/electrolyte interface.