CuxCo3-xO4-d (01) coatings for solid oxide fuel cell interconnect applications

In order to obtain the solid oxide fuel cell (SOFC) interconnect coatings with high electrical conductivity, satisfactory protectiveness, and well-fitting thermal expansion, a series of CuxCo3-xO4-$ (x = 0, 0.5, 0.8, and 1.0) coatings are prepared by supersonic spraying via subsequent sintering. The chemical composition, lattice and morphological structures, electrical properties, and thermal expansion are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), area-specific resistance (ASR), and coefficient of thermal expansion (CTE) measurements. The experimental results show that the formation of CuCo2O4 is a reversible and incomplete reaction at the elevated temperature, and the coexistence of CuO, Co3O4, and CuCo2O4 is inevitable in the coatings. The concentration of the chemicals mentioned above is highly related to the coatings' Cu:Co molar ratio. The correlation between the chemical composition and the properties is comprehensively studied in this research. The CuxCo3-xO4-$ coatings exhibit good electrical conductivity when 0 < x < 0.8, satisfactory protectiveness when 0.5 < x < 1.0, and fitting CTE with remarkable robustness through the quick heating-cooling cycles when 0.8 < x < 1.0. In general, Cu0.8Co2.2O4-$ can be an appropriate candidate to meet the advancing interconnect coating demands with high electrical conductivity, satisfactory protectiveness, and well-fitting thermal expansion properties. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.