Tailoring Mixed Ionic Electronic Conducting Nano-Particle Size through Desiccation and/or Doped Ceria Oxide Pre-Infiltration

Abstract

Mixed Ionic Electronic Conducting (MIEC) multi-cation oxide nano-particles are commonly used to enhance the performance of Solid Oxide Fuel Cell (SOFC) Nano-Composite Cathodes (NCCs) electrodes. The average MIEC NCC nano-particle size produced by the infiltration method are typically 50-60 nm in diameter and result in SOFC operating temperatures in excess of 600°C. Since MIEC particle size directly correlates with the surface area available for oxygen incorporation and hence NCC performance, the objective of this study was to determine if MIEC infiltrate particle size could be reduced through nitrate gel desiccation and/or the pre-infiltration of a nitrate decomposition catalyst (in this case nano-Gd0.1Ce0.9O1.95 (GDC)). For the La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) infiltrate particles examined here, average nano-particle sizes were reduced from 50 nm to 20 nm using both desiccation and/or pre-infiltration processing techniques. These reduced LSCF nano-particle sizes lowered the 550°C NCC polarization resistance from 0.33 Ωcm2 to 0.16 Ωcm2 with desiccation and from 0.33 Ωcm2 to 0.11 Ωcm2 with nitrate decomposition catalyst pre-infiltration.