Development of ScSZ Electrolyte by Very Low Pressure Plasma Spraying for High-Performance Metal-Supported SOFCs

Very low pressure plasma spraying (VLPPS) is an attractive method for metal-supported solid oxide fuel cells, wherein it can significantly avoid the oxidation of metal substrate. In this study, scandia-stabilized zirconia electrolyte was fabricated by VLPPS. To investigate the microstructure of coatings, the spraying distances were set to 150, 250 and 350 mm. The fractured morphology suggests that, at a relatively low deposition temperature (< 350 °C), typical lamellar structure was replaced by trans-granular structure. The apparent porosity of coatings ranges from 4.75 to 6.83%, as per the image analysis method. The ionic conductivity of coating at 250 mm was 0.068 S cm⁻¹, which was ~ 68% of bulk. The ratio of surface area to projected area of coatings surface could reach 6.53-8.30 measured by a 3D confocal laser microscope. Finally, testing cells showed a maximum output power density of 1112 mW cm⁻² and an OCV of 1.07 V at 750 °C. The ohmic resistance of whole cell was 0.1 Ω cm², and the total resistance was 0.15 Ω cm². The results suggest that very low pressure plasma spraying is a promising approach for the manufacturing of high-performance MS-SOFCs.