Electrolytic properties and nanostructural features in the La2O3-CeO2 system

Toshiyuki Mori, John Drennan, Yarong Wang, Jong Heun Lee, Ji Guang Li, Takayasu Ikegami

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Doped ceria (CeO2) compounds are fluorite-type oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, considerable interest has been shown in applications of these materials for low or intermediate temperature operation of solid-oxide fuel cells (SOFCs). In this study, the effective index was suggested to maximize the ionic conductivity in La2O3-CeO2 based oxides. The index considers the fluorite structure, and combines the expected oxygen vacancy level with the ionic radius mismatch between host and dopant cations. Using this approach, the ionic conductivity of this system has been optimized and tested under operating conditions of SOFCs. LaxCe1-xO2-δ (x = 0.125, 0.15, 0.175, and 0.20), (LaxSr1-x)0.175Ce0.825 O2-δ (x = 0.1, 0.2, and 0.4), and (La1-xSr0.2Bax)0.175 Ce0.825O2-δ (x = 0.03, 0.05, and 0.07) were prepared and characterized as the specimens with low, intermediate, and high index, respectively. The ionic conductivity was increased with increasing suggested index. The transmission electron microscopy analysis suggested that partial substitution of alkaline earth elements in place of La into Ce site contributes to a decrease of microdomain size and an improvement of conductivity. (La0.75Sr0.2Ba0.05)0.175 Ce0.825O1.891 with high index and small microdomains exhibited the highest conductivity, wide ionic domain, and good performance in SOFCs.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume150
Issue number6
DOIs
Publication statusPublished - 2003 Jul 1
Externally publishedYes

Fingerprint

Ionic conductivity
Solid oxide fuel cells (SOFC)
ion currents
Oxides
solid oxide fuel cells
Fluorspar
fluorite
oxides
Yttria stabilized zirconia
Cerium compounds
Oxygen vacancies
conductivity
Cations
yttria-stabilized zirconia
Substitution reactions
Positive ions
Earth (planet)
Doping (additives)
Transmission electron microscopy
substitutes

ASJC Scopus subject areas

  • Electrochemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Electrolytic properties and nanostructural features in the La2O3-CeO2 system. / Mori, Toshiyuki; Drennan, John; Wang, Yarong; Lee, Jong Heun; Li, Ji Guang; Ikegami, Takayasu.

In: Journal of the Electrochemical Society, Vol. 150, No. 6, 01.07.2003.

Research output: Contribution to journalArticle

Mori, Toshiyuki ; Drennan, John ; Wang, Yarong ; Lee, Jong Heun ; Li, Ji Guang ; Ikegami, Takayasu. / Electrolytic properties and nanostructural features in the La2O3-CeO2 system. In: Journal of the Electrochemical Society. 2003 ; Vol. 150, No. 6.
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