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Title: Synchrotron X-ray studies of model SOFC cathodes, part II: Porous powder cathodes

Abstract

Infiltrated La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ (LSCF) sintered porous powder cathodes for solid oxide fuel cells have been investigated by synchrotron ultra-small angle x-ray scattering (USAXS). Here, we demonstrated that atomic layer deposition (ALD) is the method for a uniform coating and liquid-phase infiltration for growing nanoscale particles on the porous LSCF surfaces. The MnO infiltrate, grown by ALD, forms a conformal layer with a uniform thickness throughout the pores evidenced by USAXS thickness fringes. The La 0.6Sr 0.4CoO 3 (LSC) and La 2Zr 2O 7 (LZO) infiltrates, grown by liquid-phase infiltration, were found to form nanoscale particles on the surfaces of LSCF particles resulting in increased surface areas. In conclusion, impedance measurements suggest that the catalytic property of LSC infiltrate, not the increased surface area of LZO, is important for increasing oxygen reduction activities.

Authors:
 [1]; ORCiD logo [2];  [3];  [4];  [1];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
  3. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  4. National Energy Technology Lab. (NETL), Morgantown, WV (United States); AECOM, Morgantown, WV (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1411042
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Solid State Ionics
Additional Journal Information:
Journal Volume: 311; Journal Issue: C; Journal ID: ISSN 0167-2738
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Chang, Kee-Chul, Ingram, Brian, Ilavsky, Jan, Lee, Shiwoo, Fuoss, Paul, and You, Hoydoo. Synchrotron X-ray studies of model SOFC cathodes, part II: Porous powder cathodes. United States: N. p., 2017. Web. doi:10.1016/j.ssi.2017.10.001.
Chang, Kee-Chul, Ingram, Brian, Ilavsky, Jan, Lee, Shiwoo, Fuoss, Paul, & You, Hoydoo. Synchrotron X-ray studies of model SOFC cathodes, part II: Porous powder cathodes. United States. doi:10.1016/j.ssi.2017.10.001.
Chang, Kee-Chul, Ingram, Brian, Ilavsky, Jan, Lee, Shiwoo, Fuoss, Paul, and You, Hoydoo. Sat . "Synchrotron X-ray studies of model SOFC cathodes, part II: Porous powder cathodes". United States. doi:10.1016/j.ssi.2017.10.001.
@article{osti_1411042,
title = {Synchrotron X-ray studies of model SOFC cathodes, part II: Porous powder cathodes},
author = {Chang, Kee-Chul and Ingram, Brian and Ilavsky, Jan and Lee, Shiwoo and Fuoss, Paul and You, Hoydoo},
abstractNote = {Infiltrated La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) sintered porous powder cathodes for solid oxide fuel cells have been investigated by synchrotron ultra-small angle x-ray scattering (USAXS). Here, we demonstrated that atomic layer deposition (ALD) is the method for a uniform coating and liquid-phase infiltration for growing nanoscale particles on the porous LSCF surfaces. The MnO infiltrate, grown by ALD, forms a conformal layer with a uniform thickness throughout the pores evidenced by USAXS thickness fringes. The La0.6Sr0.4CoO3 (LSC) and La2Zr2O7 (LZO) infiltrates, grown by liquid-phase infiltration, were found to form nanoscale particles on the surfaces of LSCF particles resulting in increased surface areas. In conclusion, impedance measurements suggest that the catalytic property of LSC infiltrate, not the increased surface area of LZO, is important for increasing oxygen reduction activities.},
doi = {10.1016/j.ssi.2017.10.001},
journal = {Solid State Ionics},
number = C,
volume = 311,
place = {United States},
year = {Sat Oct 28 00:00:00 EDT 2017},
month = {Sat Oct 28 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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  • In this work, we present synchrotron x-ray investigations of thin film La 0.6Sr 0.4Co 0.2Fe 0.8O 3-δ (LSCF) model cathodes for solid oxide fuel cells, grown on electrolyte substrates by pulse laser deposition, in situ during half-cell operations. We observed dynamic segregations of cations, such as Sr and Co, on the surfaces of the film cathodes. The effects of temperature, applied potentials, and capping layers on the segregations were investigated using a surfacesensitive technique of total external reflection x-ray fluorescence. We also studied patterned thin film LSCF cathodes using high-resolution micro-beam diffraction measurements. We find chemical expansion decreases for narrowmore » stripes. This suggests the expansion is dominated by the bulk pathway reactions. Lastly, the chemical expansion vs. the distance from the electrode contact was measured at three temperatures and an oxygen vacancy activation energy was estimated to be ~1.4 eV.« less
  • No abstract prepared.
  • The structure of 14 compounds in the series Ba{sub 2}LnTaO{sub 6} have been examined using synchrotron X-ray diffraction and found to undergo a sequence of phase transitions from I2/m monoclinic to I4/m tetragonal to Fm3-bar m cubic symmetry with decreasing ionic radii of the lanthanides. Ba{sub 2}LaTaO{sub 6} is an exception to this with variable temperature neutron diffraction being used to establish that the full series of phases adopted over the range of 15-500 K is P2{sub 1}/n monoclinic to I2/m monoclinic to R3-bar rhombohedral. The chemical environments of these compounds have also been investigated and the overbonding to themore » lanthanide cations is due to the unusually large size for the B-site in these perovskites. - Graphical abstract: The evolution of the structure across the series of double perovskites Ba{sub 2}LnTaO{sub 6} is established using a combination of synchrotron X-ray and neutron diffraction. The symmetry increases from monoclinic to tetragonal and then cubic as the size of the lanthanide decreases.« less
  • Structure refinement of high-resolution X-ray powder diffraction data of the title compound gave the composition Li{sub 1.865}CoP{sub 2}O{sub 7}, which is also verified by the ICP measurement. Two Co sites exist in the structure: one is a CoO{sub 5} square pyramid and the other is a CoO{sub 6} octahedron. They share edges and are further interconnected through P{sub 2}O{sub 7} groups, forming a three-dimensional framework, which exhibits different kinds of intersecting tunnels containing Li cations and could be of great interest in Li ion battery chemistry. The structure also exhibits cation disorder with 13.5% Co residing at the lithium (Li1)more » site. Co seems to have an average oxidation state of 2.135, as obtained from the strutural stochiometry that closely supports the magnetic susceptibility findings.« less