Supersonic spray derived Cu-Co oxide coating on SUS441 to protect the metallic interconnect and to increase stability of SOFC cathode

The interconnects for solid oxide fuel cells (SOFCs) are usually ferritic stainless steels such as SUS441. These steels have issues of oxidation and Cr diffusion under the operational high temperatures, which can cause serious deterioration of the cathode performance. In order to improve the electrode stability and the oxidation re-sistivity, this work deposits Cu-Co oxide coating on SUS441 interconnects via room-temperature supersonic spray using fine CuCo2O4 spinel-based oxide powders synthesized via a combustion process. The coating can significantly inhibit the growth of chromium oxide scale on the steel surface and increase the interconnect conductivity by a factor of 4.4 in 200-hr oxidation test in air. The coating effectively prevents Cr diffusion to the cell composed of La0 & sdot;6Sr0 & sdot;4FeO3-delta electrode and La0 & sdot;8Sr0.2Ga0.8Mg0 & sdot;2O3-delta electrolyte. As a result, the coating substantially increases the cathode performance by reducing the interfacial polarization resistance and improving the stability in 100-hr test at 800 degrees C. This study demonstrates that this high-performance protective Cu-Co oxide coating has a promising application prospect for SOFC interconnects.