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Title: Application of a crystallographic index for improvement of the electrolytic properties of the CeO{sub 2}-Sm{sub 2}O{sub 3} system

Abstract

Ceria-samaria (CeO{sub 2}-Sm{sub 2}O{sub 3}) is one of the most interesting of fluorite oxides since its oxide ionic conductivity is higher than that of yttria-stabilized zirconia and other CeO{sub 2}-based oxides. In this study, the effective index is proposed to maximize the oxide ionic conductivity in CeO{sub 2}-Sm{sub 2}O{sub 3} based oxides. Considering the crystallographic character of fluorite structure in CeO{sub 2}-Sm{sub 2}O{sub 3} system, the oxygen vacancy level was combined with the ionic radius mismatch between host and dopant cations as criteria for fast ionic conduction. Sm{sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.2 < x < 0.3), (Sm{sub 0.5}Ca{sub 0.5}){sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.175 < x < 0.3), and (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.2 < x < 0.275) were prepared and characterized as examples with low, intermediate, and high index, respectively. The oxide ionic conductivity increased with an increase of the effective index, confirming the validity of the index. Furthermore, the electrochemical properties of Sm{sub 0.25}Ce{sub 0.75}O{sub 1.88}, (Sm{sub 0.5}Ca{sub 0.5}){sub 0.225}Ce{sub 0.775}O{sub 1.84}, and (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub 0.25}Ce{sub 0.75}O{sub 1.86} were investigated in the temperature range from 700 to 1000 C as representative examples. The oxide ionic conductivity in reducing atmosphere improved with increasing index. Itmore » was found that (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub 0.25}Ce{sub 0.75}O{sub 1.86}, with the highest index value in the CeO{sub 2}-Sm{sub 2}O{sub 3} system, exhibited high oxide ionic conductivity and good performance in planar solid-oxide fuel cells.« less

Authors:
; ;
Publication Date:
Research Org.:
National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (JP)
OSTI Identifier:
20013024
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 146; Journal Issue: 12; Other Information: PBD: Dec 1999; Journal ID: ISSN 0013-4651
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; SOLID OXIDE FUEL CELLS; CERIUM OXIDES; SAMARIUM OXIDES; CRYSTALLOGRAPHY; IONIC CONDUCTIVITY

Citation Formats

Mori, Toshiyuki, Ikegami, Takayasu, and Yamamura, Hiroshi. Application of a crystallographic index for improvement of the electrolytic properties of the CeO{sub 2}-Sm{sub 2}O{sub 3} system. United States: N. p., 1999. Web. doi:10.1149/1.1392647.
Mori, Toshiyuki, Ikegami, Takayasu, & Yamamura, Hiroshi. Application of a crystallographic index for improvement of the electrolytic properties of the CeO{sub 2}-Sm{sub 2}O{sub 3} system. United States. doi:10.1149/1.1392647.
Mori, Toshiyuki, Ikegami, Takayasu, and Yamamura, Hiroshi. Wed . "Application of a crystallographic index for improvement of the electrolytic properties of the CeO{sub 2}-Sm{sub 2}O{sub 3} system". United States. doi:10.1149/1.1392647.
@article{osti_20013024,
title = {Application of a crystallographic index for improvement of the electrolytic properties of the CeO{sub 2}-Sm{sub 2}O{sub 3} system},
author = {Mori, Toshiyuki and Ikegami, Takayasu and Yamamura, Hiroshi},
abstractNote = {Ceria-samaria (CeO{sub 2}-Sm{sub 2}O{sub 3}) is one of the most interesting of fluorite oxides since its oxide ionic conductivity is higher than that of yttria-stabilized zirconia and other CeO{sub 2}-based oxides. In this study, the effective index is proposed to maximize the oxide ionic conductivity in CeO{sub 2}-Sm{sub 2}O{sub 3} based oxides. Considering the crystallographic character of fluorite structure in CeO{sub 2}-Sm{sub 2}O{sub 3} system, the oxygen vacancy level was combined with the ionic radius mismatch between host and dopant cations as criteria for fast ionic conduction. Sm{sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.2 < x < 0.3), (Sm{sub 0.5}Ca{sub 0.5}){sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.175 < x < 0.3), and (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub x}Ce{sub 1{minus}x}O{sub 2{minus}{delta}} (0.2 < x < 0.275) were prepared and characterized as examples with low, intermediate, and high index, respectively. The oxide ionic conductivity increased with an increase of the effective index, confirming the validity of the index. Furthermore, the electrochemical properties of Sm{sub 0.25}Ce{sub 0.75}O{sub 1.88}, (Sm{sub 0.5}Ca{sub 0.5}){sub 0.225}Ce{sub 0.775}O{sub 1.84}, and (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub 0.25}Ce{sub 0.75}O{sub 1.86} were investigated in the temperature range from 700 to 1000 C as representative examples. The oxide ionic conductivity in reducing atmosphere improved with increasing index. It was found that (Sm{sub 0.936}Cs{sub 0.06}Li{sub 0.004}){sub 0.25}Ce{sub 0.75}O{sub 1.86}, with the highest index value in the CeO{sub 2}-Sm{sub 2}O{sub 3} system, exhibited high oxide ionic conductivity and good performance in planar solid-oxide fuel cells.},
doi = {10.1149/1.1392647},
journal = {Journal of the Electrochemical Society},
issn = {0013-4651},
number = 12,
volume = 146,
place = {United States},
year = {1999},
month = {12}
}