Mitigation of Chromium Assisted Degradation of LSM Cathode in SOFC

Abstract

Chromium evaporation, from chromia forming ferritic alloys used in interconnect (IC) and the low cost iron and nickel base alloys used in balance of plant (BOP) during exposure to ambient air, and subsequent interactions of gaseous chromium species with the cathode is considered as one of the leading causes for the long term irreversible performance degradation in SOFC power generation systems. Although, surface coatings and alloy modifications have proved helpful in providing near term solution for the mitigation of chromium poisoning, the aforesaid remain susceptible to structural degradation in long term. A novel approach for mitigating cathode degradation by capturing gas phase chromium vapor from the air stream has been developed. Results from transpiration and symmetric electrochemical tests, conducted under simulated SOFC systems operating conditions, will be presented. Underlying thermodynamic and electrochemical processes associated with chromium evaporation and subsequent interactions with getters will be presented.