Double perovskite cathodes for proton-conducting ceramic fuel cells: are they triple mixed ionic electronic conductors?
File(s)
Author(s)
Téllez Lozano, H
Druce, J
Cooper, SJ
Kilner, JA
Type
Journal Article
Abstract
Published by National Institute for Materials Science in partnership with Taylor & Francis. 18 O and 2 H diffusion has been investigated at a temperature of 300 °C in the double perovskite material PrBaCo 2 O 5+δ (PBCO) in flowing air containing 200 mbar of 2 H 2 16 O. Secondary ion mass spectrometry (SIMS) depth profiling of exchanged ceramics has shown PBCO still retains significant oxygen diffusivity (~1.3 × 10 −11 cm 2 s −1 ) at this temperature and that the presence of water ( 2 H 2 16 O), gives rise to an enhancement of the surface exchange rate over that in pure oxygen by a factor of ~3. The 2 H distribution, as inferred from the 2 H 2 16 O − SIMS signal, shows an apparent depth profile which could be interpreted as 2 H diffusion. However, examination of the 3-D distribution of the signal shows it to be nonhomogeneous and probably related to the presence of hydrated layers in the interior walls of pores and is not due to proton diffusion. This suggests that PBCO acts mainly as an oxygen ion mixed conductor when used in PCFC devices, although the presence of a small amount of protonic conductivity cannot be discounted in these materials.
Date Issued
2017-12-04
Date Acceptance
2017-11-06
Citation
Science and Technology of Advanced Materials, 2017, 18 (1), pp.977-986
ISSN
1468-6996
Publisher
Taylor & Francis
Start Page
977
End Page
986
Journal / Book Title
Science and Technology of Advanced Materials
Volume
18
Issue
1
Copyright Statement
© 2017 The author(s). Published by national institute for Materials Science in partnership with Taylor & francis.
This is an open access article distributed under the terms of the creative commons attribution license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This is an open access article distributed under the terms of the creative commons attribution license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EP/P026478/1
Subjects
0912 Materials Engineering
Materials
Publication Status
Published