Chromium Poisoning of Cathodes in Solid Oxide Fuel Cells and its Mitigation Employing CuMn1.8O4 Spinel Coatings on Interconnects

Abstract

Chromium (Cr) poisoning of cathodes from chromia-forming alloy interconnects is one of the major challenges in long-term operation of solid oxide fuel cell stacks. To mitigate the effect of Cr-poisoning, surface coating of interconnect for reducing Cr vaporization is necessary. In this study, the candidate interconnect material (Crofer22H) with no protective coating, that with commercial CuMn2O4 spinel coating, and the one with lab-developed CuMn1.8O4 spinel coating were investigated. With these interconnects as meshes, anode-supported solid oxide fuel cells (SOFCs) with Sr-doped LaMnO3 based cathode were electrochemically tested at 800 °C for up to 288 hours. Comparing the mitigating effects of the two types of Cu-Mn spinel interconnect coatings on Cr-poisoning of the SOFC cathodes, it was observed that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in cell performance and significantly less Cr-containing deposits near the cathode/electrolyte interface after the test.