Effect of Infiltrate Solution Additives on Samarium Strontium Cobaltite -Cerium Gadolinium Oxide Nano-Composite SOFC Cathodes

摘要

Nano-composite SSC (Sm_(0.5)Sr_(0.5)CoO_(3-x))-GDC (Ce_(0.9)Gd_(0.1)O_(1.95))Solid Oxide Fuel Cell cathodes were produced by infiltrating SSCnitrate solutions with/without additives into GDC scaffolds. X-raydiffraction indicated that fired precursor solutions containing thesurfactant Triton X-100 had less secondary phases than similarlyprocessed pure nitrate solutions. Further, precursor solutionscontaining citric acid, a chelating agent, produced nearly phasepureSSC after 1 hour at 800°C. These solution additives did nothave a large effect on the cathode polarization resistance. Incontrast, alterations of the infiltration procedure influenced theSSC nano-particle size and hence the polarization resistance.Polarization resistances of 0.1 Ω·cm~2 at 600°C were achieved witha single infiltration of concentrated solution. Polarizationresistance predictions made using microstructural observations anda modified Tanner, Fung, Virkar model were found to be within40% (without fitting parameters) of the experimentally measuredvalues, regardless of the testing temperature, cathode thickness,solution additives, and cathode synthesis conditions.