High Surface Area SOFC Electrode Materials Prepared at Traditional Sintering Temperatures

Abstract

Solid oxide fuel cell (SOFC) electrode materials with surface areas up to 99 m2·g−1 were prepared at traditional sintering temperatures, 1050°C–1350°C, by sintering hybrid inorganic-organic materials in an inert atmosphere followed by calcination in air at 700°C. The electrode materials investigated were yttria-stabilized zirconia (YSZ), lanthanum strontium cobalt ferrite (LSCF), gadolinia doped ceria (GDC), and strontium titanate (STO). During sintering, an amorphous carbon template forms in situ and remains throughout the sintering process, aiding in the creation and preservation of mixed-metal-oxide nanomorphology. The carbon template is removed during subsequent calcination in air at 700°C, leaving behind a nanostructured ceramic. Phase stability, carbon template concentration, and specific surface area was determined for each mixed-metal-oxide. Final specific surface areas up to 83, 66, 95, and 99 m2·g−1 were achieved for YSZ, LSCF, GDC, and STO, respectively. The impact of high surface area YSZ on symmetrical YSZ-lanthanum strontium ferrite (LSF) cathode cell performance was evaluated in the temperature range of 550°C–800°C. Adding nanostructured YSZ decreased the electrochemical impedance by 45% at 550°C. The performance improvement lessened with increasing temperature, and at 800°C there was essentially no improvement. The findings reveal a promising approach to improving low temperature SOFC performance.