Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4 + δ: Fabrication and characterisation of dip-coated electrolyte layers

Fabrication conditions to obtain dense electrolyte double layers on a porous micro-tubular cathode substrate were investigated. Porous tubes of a nickelate material, Nd1.95NiO4 + δ, were fabricated by cold-isostatic pressing (CIP) and sintering. Thin films of electrolyte powders Ce0.9Gd0.1O1.95 (GDC) and Zr0.89Sc0.1Ce0.01O1.95 (SSZ) were applied by dip-coating in aqueous suspensions. Electrolyte powders had been attrition-milled to decrease their particle size and densification temperature. The quantity of polyacrylic acid (PAA) as dispersant was optimised by ζ-potential measurements. The densification behaviour was studied by dilatometry and SEM-imaging. A sintering temperature of 1250 °C was found to densify GDC whereas SSZ-layers remained slightly porous.