Yttria‐stabilized zirconia (YSZ, 8 mol% Y2O3) scaffolds, with surface areas up to 68 m2/g, were prepared by sintering hybrid inorganic‐organic propylene oxide (PO) gels in an argon atmosphere between 1050°C and 1350°C. During sintering, a hard carbon template forms in situ that preserves the scaffold nanomorphology. The carbon template is completely removed postsinter by heating in air to 700°C. Surface areas of 24, 14, 3.2, and 2.4 m2/g were achieved for argon sintering temperatures of 1050°C, 1150°C, 1250°C, and 1350°C, respectively. By adding glucose to the gel formulation, the amount of carbon template increases from 4 to 59 wt% and the surface area increases from 14 to 68 m2/g. Remarkably, the surface area only decreases to 59 m2/g upon heating to 900°C in air. This in situ carbon templating approach offers a flexible platform to create and preserve highly desirable surface areas and nanomorphologies while sintering at high temperatures. The utility of this approach to improve low‐temperature solid oxide fuel cell electrode performance is discussed.

Solid oxide fuel cell (SOFC) electrode materials with surface areas up to 99 m 2 • 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 m 2 • 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.

Interconnected networks of 10-30 nm yttria-stabilized zirconia (YSZ) nanoparticles dramatically enhance both the electrocatalytic activity and bulk charge transport of commercial lanthanum strontium manganite (LSM)-YSZ solid oxide fuel cell (SOFC) cathodes. The improvement in both electrode functions increases the maximum power density of the commercial SOFC by 90%. In comparison, modifying cathodes with lanthanum strontium cobalt ferrite (LSCF) and praseodymium barium cobaltite (PBC) nanoparticles, highly active catalysts with mixed ionic-electronic conductivity (MIEC), only enhances electrocatalytic activity. The combination of dual enhanced electrode functions with nanoYSZ results in a maximum power density that is 50% and 11% higher than LSCF and PBC, respectively. Finally, the performance stability over time is highest for nanoYSZ modified cells.

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) scaffolds with tunable specific surface areas up to 80 m·g. An aqueous solution of a zirconium salt, yttrium salt, and glucose is mixed with propylene oxide (PO) to form a gel. The gel is dried under ambient conditions to form a xerogel. The xerogel is pressed into pellets and then sintered in an argon atmosphere. During sintering, a YSZ ceramic phase forms and the organic components decompose, leaving behind amorphous carbon. The carbon formed in situ serves as a hard template, preserving a high surface area YSZ nanomorphology at sintering temperature. The carbon is subsequently removed by oxidation in air at low temperature, resulting in a porous, nanostructured YSZ scaffold. The concentration of the carbon template and the final scaffold surface area can be systematically tuned by varying the glucose concentration in the gel synthesis. The carbon template concentration was quantified using thermogravimetric analysis (TGA), the surface area and pore size distribution was determined by physical adsorption measurements, and the morphology was characterized using scanning electron microscopy (SEM). Phase purity and crystallite size was determined using X-ray diffraction (XRD). This fabrication approach provides a novel, flexible platform for realizing unprecedented scaffold surface areas and nanomorphologies for ceramic-based electrochemical energy conversion applications, e.g. solid oxide fuel cell (SOFC) electrodes.

The thermochemical stability of nanoscale yttria-stabilized-zirconia (nYSZ), processed via in situ carbon templating, was studied between 850 • C-1350 • C in four sintering atmospheres: Ar, N 2 , H 2 , and humidified H 2 . The in situ carbon templating method generates nanoscale ceramic particles surrounded by an amorphous carbon template upon sintering. The carbon template is subsequently removed by low temperature oxidation, leaving behind nanoscale ceramic particles. In Ar and H 2 , a ZrC impurity formed at temperatures ≥1150 • C. In humidified H 2 , either a ZrC impurity formed or the carbon template oxidized. In N 2 , ZrC was not observed over the temperature range studied and the carbon template was preserved. After carbon template removal, the nYSZ surface areas were high for Ar, H 2 , and N 2 : 55-99 m 2 • g −1 . For humidified H 2 , nYSZ surface area decreased as the carbon template was lost. Finally, nYSZ, processed in N 2 at 850 • C and 1250 • C, was integrated into symmetric YSZ-Lanthanum Strontium Ferrite (YSZ-LSF) cathode cells. The addition of nYSZ decreased cathode non-ohmic resistance, at 550 • C in air, by 40% and 27% for nYSZ processed at 850 • C and 1250 • C, respectively. This work demonstrates that N 2 is a thermochemically stable atmosphere for in situ carbon templating and that the resulting nYSZ considerably improves electrode performance.