Electrochemical Performance and Stability of the Cathode for Solid Oxide Fuel Cells IV. On the Ohmic loss in anode supported button cells with LSM or LSCF cathodes

Journal Article · Sat May 08 04:00:00 EDT 2010 · Journal of the Electrochemical Society, 157(6):b964-b969

DOI:https://doi.org/10.1149/1.3417064· OSTI ID:991990

Lu, Zigui; Zhou, Xiao Dong; Templeton, Jared W; Stevenson, Jeffry W

Anode-supported solid oxide fuel cells (SOFC) with a variety of YSZ electrolyte thicknesses were fabricated by tape casting and lamination. The preparation of the YSZ electrolyte tapes with various thicknesses was accomplished by using doctor blades with different gaps between the precision machined, polished blade and the casting surface. The green tape was cut into discs, sintered at 1385°C for 2 h, and subsequently creep-flattened at 1350°C for 2 h. Either LSCF with an SDC interlayer or LSM+YSZ composite was used as the cathode material for the fuel cells. The ohmic resistances of these anode-supported fuel cells were characterized by electrochemical impedance spectroscopy at temperatures from 500°C to 750°C. A linear relationship was found between the ohmic resistance of the fuel cell and the YSZ electrolyte thickness at all the measuring temperatures for both LSCF and LSM+YSZ cathode fuel cells. The ionic conductivities of the YSZ electrolyte, derived for the fuel cells with LSM+YSZ or LSCF cathodes, were independent of the cathode material and cell configuration. The ionic conductivities of the YSZ electrolyte was slightly lower than that of the bulk material, possibly due to Ni-doping into the electrolyte. The fuel cell with a SDC interlayer and LSCF cathode showed larger intercept resistance than the fuel cell with LSM+YSZ cathode, which was possibly due to the imperfect contact between the SDC interlayer and the YSZ electrolyte and the migration of Zr into the SDC interlayer to form an insulating solid solution during cell fabrication. Calculations of the contribution of the YSZ electrolyte to the total ohmic resistance showed that YSZ was still a satisfactory electrolyte at temperatures above 650°C. Explorations should be directed to reduce the intercept resistance to achieve significant improvement in cell performance.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 991990
• Report Number(s): PNNL-SA-72068; AA2530000
• Journal Information: Journal of the Electrochemical Society, 157(6):b964-b969, Journal Name: Journal of the Electrochemical Society, 157(6):b964-b969 Journal Issue: 6 Vol. 157; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
ACCURACY
ANODES
CASTING
CATHODES
CONFIGURATION
ELECTRIC CONDUCTIVITY
ELECTROLYTES
FABRICATION
FUEL CELLS
IMPEDANCE
PERFORMANCE
SOLID OXIDE FUEL CELLS
SOLID SOLUTIONS
SPECTROSCOPY
STABILITY
THICKNESS
YSZ electrolyte thickness
ohmic resistance
solid oxide fuel cell