PROBIEN   20416
INSTITUTO DE INVESTIGACION Y DESARROLLO EN INGENIERIA DE PROCESOS, BIOTECNOLOGIA Y ENERGIAS ALTERNATIVAS
Unidad Ejecutora - UE
artículos
Título:
High resolution FIB-TEM and FIB-SEM characterization of electrode/electrolyte interfaces in solid oxide fuel cells materials
Autor/es:
SOLDATI; BAQUE; TROIANI; COTARO; SCHREIBER; CANEIRO; SERQUIS
Revista:
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2011 p. 9180 - 9188
ISSN:
0360-3199
Resumen:
A Focused Ion Beam (FIB)/lift-out technique was used
to prepare site-specific thin samples of the cathode/electrolyte
interface of Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC)
materials. The cathode under study was a nanostructured perovskite of
composition La 0.4Sr 0.6Co 0.8Fe 0.2O 3-δ (LSCF) deposited by spin
coating on a Ce 0.9Gd 0.1O 2-δ (CGO) supporting substrate. We compared
the results for a 15 μm and a 5 μm thickness cathode layers, before and
after a thermal treatment of 1000 h at 500 °C, with the aim of
simulating operation conditions. Both, Transmission (TEM) and Scanning
(SEM) Electron Microscopy, coupled with Energy Dispersive Spectroscopy
(EDS) systems, were used to characterize the composition and
nanostructure at both sides of the cathode/electrolyte interface. To our
knowledge, this is the first time that a semi-coherent interface
between LSCF and CGO was observed by Electron Diffraction as well as by
High Resolution TEM in many points at the interfacial boundary. A large
difference in total contact area was observed between the thickest and
the thinnest cathode layers, despite they present the same composition
and nano sized structure. The real contact area in the 5 μm cathode
sample is around 50% less than in the 15 μm sample due to the presence
of pores at the interface. This observation may partially explain the
difference in resistivity observed for these two half cells assemblies.
On the other side, no differences were found comparing composition and
nanostructure at the interface before and after the thermal treatment.
Thus, this study becomes fundamental to understand the role played by
the interface for improving the performance of IT-SOFC under long time
operation conditions: a necessary premise for its real application. ©
2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All
rights reserved.