Thermodynamic and Experimental Evaluation of La1xSrxMnO3±d Cathode in Presence of Cr-Containing Humidified Air

Thermodynamic predictions were carried out on the phase stability of the lanthanum manganite (LSM)/yttria-stabilized zirconia (YSZ) system in presence and absence of Cr-containing dry and humidified atmosphere over broad ranges of temperature, oxygen partial pressure, and humidity. Formation of Mn oxides, La2Zr2O7, SrZrO3, Mn(Mn,Cr)2O4 (spinel), and zirconia was predicted, in agreement with previous experimental efforts. Humidity enhances the perovskite degradation by increasing the kinetics of secondary phase formation reactions. The impact of Cr6+ poisoning is more significant in presence of humidity in the atmosphere, as volatile Cr6+ species, in the form of CrO3 and CrO2(OH)2, may diffuse into the perovskite structure and change its phase stability and properties.