SURFACE SEGREGATION STUDIES OF SOFC CATHODES: COMBINING SOFT X-RAYS AND ELECTROCHEMICAL IMPEDENCE SPECTROSCOPY

Conference · Wed Dec 01 00:00:00 EST 2010

OSTI ID:1005138

Miara, Lincoln J; Piper, L F.J.; Davis, Jacob N; Saraf, Laxmikant V; Kaspar, Tiffany C; Basu, Soumendra; Smith, K E; Pal, Uday B; Gopalan, Srikanth

A system to grow heteroepitaxial thin-films of solid oxide fuel cell (SOFC) cathodes on single crystal substrates was developed. The cathode composition investigated was 20% strontium-doped lanthanum manganite (LSM) grown by pulsed laser deposition (PLD) on single crystal (111) yttria-stabilized zirconia (YSZ) substrates. By combining electrochemical impedance spectroscopy (EIS) with x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy XAS measurements, we conclude that electrically driven cation migration away from the two-phase gas-cathode interface results in improved electrochemical performance. Our results provide support to the premise that the removal of surface passivating phases containing Sr2+ and Mn2+, which readily form at elevated temperatures even in O2 atmospheric pressures, is responsible for the improved cathodic performance upon application of a bias.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1005138
• Report Number(s): PNNL-SA-70211; 30429; KP1704020; TRN: US201105%%201
• Resource Relation: Conference: Materials Research Society (MRS) Symposium Proceedings: Catalytic Materials for Energy, Green Processes and Nanotechnology, November 30 - December 3, 2009, Boston, MA, 1217:145-150
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
ABSORPTION SPECTROSCOPY
ATMOSPHERIC PRESSURE
CATHODES
CATIONS
DEPOSITION
IMPEDANCE
LANTHANUM
LASERS
MONOCRYSTALS
PERFORMANCE
PHOTOEMISSION
REMOVAL
SEGREGATION
SOLID OXIDE FUEL CELLS
SPECTROSCOPY
SUBSTRATES
THIN FILMS
X-RAY PHOTOELECTRON SPECTROSCOPY
Environmental Molecular Sciences Laboratory