Phase decomposition in the chromium- and silicon-poisoned IT-SOFC cathode materials La0.6Sr0.4CoO3-δ and La2NiO4+δ

Nina Schrödl, Edith Bucher, Christian Gspan, Andreas Egger, Christian Ganser, Christian Teichert , Ferdinand Hofer, Werner Sitte

Publikation: Beitrag in einer FachzeitschriftArtikelForschungBegutachtung

Abstract

Chromium- and silicon-poisoned samples of the intermediate temperature solid oxide fuel cell (IT-SOFC)
cathode materials La0.6Sr0.4CoO3-δ (LSC) and La2NiO4+δ (LNO) were investigated by transmission electron
microscopy (TEM) with energy dispersive X-ray spectroscopy (EDXS), electron energy loss spectroscopy
(EELS), convergent beam electron diffraction (CBED), as well as by atomic force microscopy (AFM). Analytical
TEM revealed phase decomposition of the original, oxygen exchange-active materials LSC and LNO, and the formation
of secondary phases after 3500 h of testing at 700 °C. In the case of LSC, the phases SrCrO4, Co3O4, and
CoCr2-xCoxO4 as well as a La‐chromate phasewith unknown stoichiometrywere found in the near-surface region
and at the grain boundaries. Transport of cations, especially Sr and Cr, along the grain boundaries seems to play a
key role in the degradation of LSC. AFMwas used to determine the three-dimensional shape including interplanar
facet angles of SrCrO4 crystallites. In the case of the Sr-free material LNO, the formation of La‐silicate and La-Nichromate
phases was observed, which seems to proceed from the surface toward the bulk. Based on the
experimental results, tentative mechanisms for the degradation processes are suggested.
© 2016 Elsevier B.V. All
Originalspracheenglisch
Seiten (von - bis)14-21
Seitenumfang8
FachzeitschriftSolid State Ionics
Jahrgang288
DOIs
PublikationsstatusVeröffentlicht - 2016

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ASJC Scopus subject areas

  • !!Materials Science(all)

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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