Chrome Poisoning of Non-Manganiferous Cathode Materials in Solid Oxide Fuel Cells (SOFCs)

This work is focused on the degradation effect of chrome poisoning on LSCF cathodes for high temperature SOFCs aimed at an increase of the cell durability. Therefore the electrochemical performance of single cells is investigated at open cell voltage (OCV) and polarizations of 0.5, 0.75 and 1 A*cm-2 as well as at temperatures of 900 and 700°C in presence/absence of a chrome source. To identify the cathode related processes of the impedance spectra without anode contributions, symmetrical half cells were tested as well. It is observed that in presence of a chrome source the ohmic as well as the polarization resistances increase. At a temperature of 900 °C and a humidity of 3.5 %, the polarization resistance shows a stronger increase at current densities above 0.75 A*cm-² whereas the polarization resistance remains linear. Furthermore, measurements at 700 °C confirmed that also the operation temperature serves as a factor for accelerated chrome related cell degradation.