The effect of molybdenum on chromium deposition at (La0.8Sr0.2)0.95MnO3-δ cathode of solid oxide fuel cells

The effect of addition of molybdenum in FeCrMn based alloy on the chromium deposition and poisoning of LSM cathodes is investigated at 800 °C by electrochemical impedance spectroscopy and microstructure analysis. The FeCrMnMo ferrite stainless steel metallic interconnect shows much less Cr deposition and poisoning on the LSM cathodes as compared with the FeCrMn alloy. The addition of Mo into the alloy suppressed Cr evaporation from interconnects, decreased the degradation of cathode performance caused by Cr. According to SEM results, MoO3 and MnMoO4 is observed at the depositional area. The segregated MnO from LSM cathode can act as a nuclei agent, and react with vaporized Mo to form Mo-contained oxide particles, which will not inhibit the oxygen reduction reactions in the three phase boundary (TPB). As a result, suitable addition of Mo into the interconnect alloy can effectively alleviate the Cr poisoning of the LSM cathode.