Overcoming phase instability of RBaCo2O5+δ (R = y and Ho) by Sr substitution for application as cathodes in solid oxide fuel cells

Jung Hyun Kim; Young Nam Kim; Zhonghe Bi; Arumugam Manthiram; M. Parans Paranthaman; Ashfia Huq

doi:10.1016/j.ssi.2013.09.001

Overcoming phase instability of RBaCo₂O_5+δ (R = y and Ho) by Sr substitution for application as cathodes in solid oxide fuel cells

Jung Hyun Kim, Young Nam Kim, Zhonghe Bi, Arumugam Manthiram, M. Parans Paranthaman, Ashfia Huq

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

Phase instabilities of the RBaCo₂O_5+δ (R = Y and Ho) layered-perovskites and their decompositions into RCoO₃ and BaCoO_3-z at 800 C in air were investigated. The phase instability will restrict their high temperature applications such as cathodes in solid oxide fuel cells (SOFC). However, appropriate amount of Sr substitution (≥ 60% for R = Y and ≥ 70% for R = Ho) for Ba successfully stabilized the R(Ba_1-xSr_x)Co₂O_5+δ phase at elevated temperatures. This can be explained to be due to the decrease in oxygen vacancies in the R-O layer, decrease in RO bond length, and consequent improvement in structural integrity. In addition, the Sr substitution (x = 0.6-1.0) for Ba provided added benefit with respect to the chemical stability against Ce_0.8Gd_0.2O_1.9 (GDC) electrolyte, which is a critical requirement for the cathodes in SOFC. Among the various compositions investigated, the Y(Ba_0.3Sr_0.7)Co ₂O_5+δ + GDC composite cathode delivered the optimum electrochemical performances with a stable phase, demonstrating the potential as a cathode in SOFC.

Original language	English
Pages (from-to)	81-87
Number of pages	7
Journal	Solid State Ionics
Volume	253
DOIs	https://doi.org/10.1016/j.ssi.2013.09.001
State	Published - 2013

Funding

This work was sponsored by the Laboratory Directed Research and Development (LDRD) Program of Oak Ridge National Laboratory (ORNL) . Jung-Hyun Kim and Zhonghe Bi acknowledge the support of the ORISE postdoctoral fellowship . Support (MPP) for electrochemical measurements was provided by Office of Basic Energy Sciences, Materials Sciences and Engineering Division, US Department of Energy . The authors would also like to thank Andrew E. Payzant of Neutron Scattering Science Division in ORNL for supporting XRD measurements. Financial and technical supports by Spallation Neutron Source, ORNL SHaRE user facility, and Center for Nanophase Materials Sciences which are sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy , under contract DE-AC05-00OR22725 with UT-Battelle, LLC, are gratefully acknowledged. Financial support by the Welch Foundation grant F-1254 for the work carried out at the University of Texas at Austin is gratefully acknowledged by Young Nam Kim and Arumugam Manthiram.

Keywords

HoBaCoO
Layered perovskite cathode
Phase decomposition
Solid oxide fuel cells
YBaCoO

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10.1016/j.ssi.2013.09.001

Cite this

@article{bfb8547034244915be9f1197e0f8c16f,

title = "Overcoming phase instability of RBaCo2O5+δ (R = y and Ho) by Sr substitution for application as cathodes in solid oxide fuel cells",

abstract = "Phase instabilities of the RBaCo2O5+δ (R = Y and Ho) layered-perovskites and their decompositions into RCoO3 and BaCoO3-z at 800 C in air were investigated. The phase instability will restrict their high temperature applications such as cathodes in solid oxide fuel cells (SOFC). However, appropriate amount of Sr substitution (≥ 60% for R = Y and ≥ 70% for R = Ho) for Ba successfully stabilized the R(Ba1-xSrx)Co2O5+δ phase at elevated temperatures. This can be explained to be due to the decrease in oxygen vacancies in the R-O layer, decrease in RO bond length, and consequent improvement in structural integrity. In addition, the Sr substitution (x = 0.6-1.0) for Ba provided added benefit with respect to the chemical stability against Ce0.8Gd0.2O1.9 (GDC) electrolyte, which is a critical requirement for the cathodes in SOFC. Among the various compositions investigated, the Y(Ba0.3Sr0.7)Co 2O5+δ + GDC composite cathode delivered the optimum electrochemical performances with a stable phase, demonstrating the potential as a cathode in SOFC.",

keywords = "HoBaCoO, Layered perovskite cathode, Phase decomposition, Solid oxide fuel cells, YBaCoO",

author = "Kim, {Jung Hyun} and Kim, {Young Nam} and Zhonghe Bi and Arumugam Manthiram and Paranthaman, {M. Parans} and Ashfia Huq",

year = "2013",

doi = "10.1016/j.ssi.2013.09.001",

language = "English",

volume = "253",

pages = "81--87",

journal = "Solid State Ionics",

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T1 - Overcoming phase instability of RBaCo2O5+δ (R = y and Ho) by Sr substitution for application as cathodes in solid oxide fuel cells

AU - Kim, Jung Hyun

AU - Kim, Young Nam

AU - Bi, Zhonghe

AU - Manthiram, Arumugam

AU - Paranthaman, M. Parans

AU - Huq, Ashfia

PY - 2013

Y1 - 2013

N2 - Phase instabilities of the RBaCo2O5+δ (R = Y and Ho) layered-perovskites and their decompositions into RCoO3 and BaCoO3-z at 800 C in air were investigated. The phase instability will restrict their high temperature applications such as cathodes in solid oxide fuel cells (SOFC). However, appropriate amount of Sr substitution (≥ 60% for R = Y and ≥ 70% for R = Ho) for Ba successfully stabilized the R(Ba1-xSrx)Co2O5+δ phase at elevated temperatures. This can be explained to be due to the decrease in oxygen vacancies in the R-O layer, decrease in RO bond length, and consequent improvement in structural integrity. In addition, the Sr substitution (x = 0.6-1.0) for Ba provided added benefit with respect to the chemical stability against Ce0.8Gd0.2O1.9 (GDC) electrolyte, which is a critical requirement for the cathodes in SOFC. Among the various compositions investigated, the Y(Ba0.3Sr0.7)Co 2O5+δ + GDC composite cathode delivered the optimum electrochemical performances with a stable phase, demonstrating the potential as a cathode in SOFC.

AB - Phase instabilities of the RBaCo2O5+δ (R = Y and Ho) layered-perovskites and their decompositions into RCoO3 and BaCoO3-z at 800 C in air were investigated. The phase instability will restrict their high temperature applications such as cathodes in solid oxide fuel cells (SOFC). However, appropriate amount of Sr substitution (≥ 60% for R = Y and ≥ 70% for R = Ho) for Ba successfully stabilized the R(Ba1-xSrx)Co2O5+δ phase at elevated temperatures. This can be explained to be due to the decrease in oxygen vacancies in the R-O layer, decrease in RO bond length, and consequent improvement in structural integrity. In addition, the Sr substitution (x = 0.6-1.0) for Ba provided added benefit with respect to the chemical stability against Ce0.8Gd0.2O1.9 (GDC) electrolyte, which is a critical requirement for the cathodes in SOFC. Among the various compositions investigated, the Y(Ba0.3Sr0.7)Co 2O5+δ + GDC composite cathode delivered the optimum electrochemical performances with a stable phase, demonstrating the potential as a cathode in SOFC.

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