Comparison of Cu-Mn and Mn-Co spinel coatings for solid oxide fuel cell interconnects

Electrophoretic deposition (EPD) of protective coatings on solid oxide fuel cell (SOFC) in-terconnects is an efficient method to mitigate 'chromium poisoning', which is a primary reason for degradation of fuel cell performance. Cu-Mn spinels and Mn-Co spinels are the most widely used materials for such coatings. In this study, four spinel coatings were examined; CuMn2O4, CuNi0.2Mn1.8O4, MnCo2O4, and MnFe0.34Co1.66O4. The coatings were evaluated on multiple criteria; including phase stability, microstructural stability, con-ductivity, Cr gettering ability, ability to act as a diffusion barrier to outward chromium and inward oxygen diffusion, and the ability to limit the increase in the area specific resistance (ASR) during high temperature oxidation exposures. The results showed that, while different coatings have best individual characteristics, overall CuNi0.2Mn1.8O4 was the best candidate for the coatings operating in the intermediate temperature range due to its best sinterability, highest conductivity, lowest ASR, phase stability over the operational tem-perature range, lower cost and good resistance to outward chromium and inward oxygen diffusion.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.