Research Progresses in the Preparation of Spinel Coatings on the Surface of SOFC Ferrite Stainless Steel Interconnectors

As one of the important components of solid oxide fuel cell (SOFC), interconnector mainly plays the role of supporting connecting circuit and isolating fuel gas and oxidation gas. At present, with the development of SOFC to medium and low operation temperatures (600-800°C), ferritic stainless steel (FSS) has become the most potential SOFC interconnector material because of its excellent electric and heat conductivity, easy processing, good coefficient of thermal expansion (CTE) compatibility with other components and low price. However, in the SOFC working environment, FSS will produce Cr volatile chemical compounds, resulting in "Cr poisoning" of the cathode and performance degradation of the cell, which restricts the commercial application of SOFC. Spinel protective coating on the surface of FSS can effectively inhibit the volatilization of Cr compounds and improve the oxidation resistance of FSS interconnectors. Therefore, the development and preparation of spinel coating on the surface of FSS connectors has become a research hotspot in this field. In this paper, the materials of spinel coating commonly used on the surface of FSS interconnector are summarized, the main preparation methods, characteristics and research progresses on spinel coatings are reviewed, and the future development trends in this field are also proposed.