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Title: Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites: New cathode materials for solid-oxide fuel cells

Abstract

An improved cathode material for a solid-oxide fuel cell would be a mixed electronic and oxide-ion conductor with a good catalytic activity for oxygen reduction at an operating temperature T{sub op} {le} 700 C and a thermal expansion matched to that of the electrolyte and interconnect. The authors report on the properties of Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites that meet these criteria. Single-phase regions were determined by X-ray diffraction, and thermogravimetric analysis measurements were used to obtain the temperatures above which oxygen loss, and hence oxide-ion conductivity, occurs. The conductivity and Seebeck measurements indicate the coexistence of both p-type and n-type polaronic charge carriers resulting from an overlap of the Ni{sup III}/Ni{sup 2+} redox couple with the low-spin/intermediate-spin Co{sup IV}/Co{sup III} and high-spin Fe{sup 4+}/Fe{sup 3+} redox couples. Motional enthalpies {Delta}H{sub m} = 0.03, 0.02, and 0.08 eV, respectively, were estimated for Ni{sup 2+}, Co{sup IV}, and Fe{sup 4+} polarons. Optimal compositions have percolation pathways between dopants. Comparisons with transport data for the conventional cathode materials La{sub 1{minus}x}Sr{sub x}CoO{sub 3{minus}{delta}} and La{sub 1{minus}x}Sr{sub x}MnO{sub 3} indicate superior cathode performance can be expected.

Authors:
; ;  [1]
  1. Univ. of Texas, Austin, TX (United States). Texas Materials Inst.
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
659127
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 145; Journal Issue: 9; Other Information: PBD: Sep 1998
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; 36 MATERIALS SCIENCE; SOLID ELECTROLYTE FUEL CELLS; CATHODES; LANTHANUM OXIDES; COBALT OXIDES; IRON OXIDES; DOPED MATERIALS; IONIC CONDUCTIVITY; THERMODYNAMIC PROPERTIES; MICROSTRUCTURE

Citation Formats

Huang, K, Lee, H Y, and Goodenough, J B. Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites: New cathode materials for solid-oxide fuel cells. United States: N. p., 1998. Web. doi:10.1149/1.1838789.
Huang, K, Lee, H Y, & Goodenough, J B. Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites: New cathode materials for solid-oxide fuel cells. United States. https://doi.org/10.1149/1.1838789
Huang, K, Lee, H Y, and Goodenough, J B. Tue . "Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites: New cathode materials for solid-oxide fuel cells". United States. https://doi.org/10.1149/1.1838789.
@article{osti_659127,
title = {Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites: New cathode materials for solid-oxide fuel cells},
author = {Huang, K and Lee, H Y and Goodenough, J B},
abstractNote = {An improved cathode material for a solid-oxide fuel cell would be a mixed electronic and oxide-ion conductor with a good catalytic activity for oxygen reduction at an operating temperature T{sub op} {le} 700 C and a thermal expansion matched to that of the electrolyte and interconnect. The authors report on the properties of Sr- and Ni-doped LaCoO{sub 3} and LaFeO{sub 3} perovskites that meet these criteria. Single-phase regions were determined by X-ray diffraction, and thermogravimetric analysis measurements were used to obtain the temperatures above which oxygen loss, and hence oxide-ion conductivity, occurs. The conductivity and Seebeck measurements indicate the coexistence of both p-type and n-type polaronic charge carriers resulting from an overlap of the Ni{sup III}/Ni{sup 2+} redox couple with the low-spin/intermediate-spin Co{sup IV}/Co{sup III} and high-spin Fe{sup 4+}/Fe{sup 3+} redox couples. Motional enthalpies {Delta}H{sub m} = 0.03, 0.02, and 0.08 eV, respectively, were estimated for Ni{sup 2+}, Co{sup IV}, and Fe{sup 4+} polarons. Optimal compositions have percolation pathways between dopants. Comparisons with transport data for the conventional cathode materials La{sub 1{minus}x}Sr{sub x}CoO{sub 3{minus}{delta}} and La{sub 1{minus}x}Sr{sub x}MnO{sub 3} indicate superior cathode performance can be expected.},
doi = {10.1149/1.1838789},
url = {https://www.osti.gov/biblio/659127}, journal = {Journal of the Electrochemical Society},
number = 9,
volume = 145,
place = {United States},
year = {1998},
month = {9}
}