Calcium- and Cobalt-doped Yttrium Chromites as an Interconnect Material for Solid Oxide Fuel Cells

Journal Article · Fri Apr 23 04:00:00 EDT 2010 · Journal of the Electrochemical Society, 157(6):B856-B861

DOI:https://doi.org/10.1149/1.3337156· OSTI ID:982306

Yoon, Kyung J; Cramer, Carolyn N; Thomsen, Edwin C; Coyle, Christopher A; Coffey, Greg W; Marina, Olga A

The structural, thermal and electrical characteristics of calcium- and cobalt-doped yttrium chromites were studied for a potential use as the interconnect material in high temperature solid oxide fuel cells (SOFCs) as well as other high temperature electrochemical and thermoelectric devices. The Y0.8Ca0.2Cr1-xCoxO3±δ (x=0, 0.1, 0.2, 0.3) compositions had single phase orthorhombic perovskite structures in the wide range of oxygen pressures. Sintering behavior was remarkably enhanced upon cobalt doping and densities 95% and 97% of theoretical density were obtained after sintering at 1300oC in air, when x was 0.2 and 0.3, respectively. The electrical conductivity in both oxidizing and reducing atmospheres was significantly improved with cobalt content, and values of 49 and 10 S/cm at 850oC and 55 and 14 S/cm at 950oC in air and forming gas, respectively, were reported for x=0.2. The conductivity increase was attributed to the charge carrier density increase upon cobalt substitution for chromium confirmed with Seebeck measurements. The thermal expansion coefficient (TEC) was increased with cobalt content and closely matched to that of an 8 mol% yttria-stabilized zirconia (YSZ) electrolyte for 0.1 ≤ x ≤ 0.2. The chemical compatibility between Y0.8Ca0.2Cr1-xCoxO3±δ and YSZ was evaluated firing the two at 1400oC and no reaction products were found if x value was kept lower than 0.2.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 982306
• Report Number(s): PNNL-SA-69520; AA2530000
• Journal Information: Journal of the Electrochemical Society, 157(6):B856-B861, Journal Name: Journal of the Electrochemical Society, 157(6):B856-B861 Journal Issue: 6 Vol. 157; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AIR
ATMOSPHERES
BEHAVIOR
CALCIUM
CHARGE CARRIERS
CHROMITES
CHROMIUM
COBALT
COMPATIBILITY
Ceramic Interconnect
DENSITY
Doped Yttrium Chromite
ELECTRIC CONDUCTIVITY
ELECTROLYTES
EQUIPMENT
Electronic Conductivity
MATERIALS
OXYGEN
PEROVSKITE
POTENTIALS
Perovskite
RANGE
SINTERING
SOLID OXIDE FUEL CELLS
Sinterability
Solid Oxide Fuel Cell
TEMPERATURE RANGE 0400-1000 K
THERMAL EXPANSION
YTTRIUM