A study of screen printed yttria-stabilized zirconia layers for solid oxide fuel cells

Screen printing of thin yttria-stabilized zirconia (YSZ) electrolytes onto NiO-YSZ anode supports was studied. Experimental parameters studied included screen printing ink composition and rheology, screen printer settings, NiO-YSZ anode support thickness pre-fire temperature, sintering temperature, and ramp rate. Viscoelastic rheology of the inks versus solids loading was measured and correlated with print results. Increasing ink solids loading from 20 to 40 vol% increased the thickness and roughness of fired layers, but did not affect film density. Bi-layer curvature after co-firing depended strongly on ink solids loading, support thickness, and support pre-fire temperature. A simple non-destructive permeability test apparatus was used to determine whether electrolytes were sufficiently dense to allow good cell performance. Cell test results at 800 degrees C showed open circuit voltage values from 1.05 to 1.089 V, compared to a predicted Nernst voltage of 1.10 V, for optimized processing conditions. Power densities as high as 1.45 W/cm(2) were attained, and impedance spectroscopy analysis showed a resistivity value of approximate to 46 Omega(.)cm for the screen printed YSZ films.