Anisotropic oxide ion conduction in melilite intermediate temperature electrolytes

Fengxia Wei, Hripsime Gasparyan, Philip Keenan, Matthias Gutmann, Yanan Fang, Tom Baikie, John Claridge, Peter Slater, Christian Kloc, Tim White

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Electrolytes with oxide ion conductivities higher than 10−2 S cm−1 at moderate temperatures (∼500–900 °C) offer the possibility for solid oxide fuel cells to operate with less maintenance. This study of [A1+xB1−x]2[Ga]2[Ga2O7+x/2]2 (0 ≤ x ≤ 0.5) (A = La, Nd; B = Ca, Sr) layered-melilite found that in large single crystals intralayer oxide ion conduction is dominant. This anisotropic behavior arises by relaxation about the interstitial oxygen through changes in the interlayer A and Ga coordination, and at 850 °C conductivities are ∼0.008 S cm−1 along the c direction and ∼0.036 S cm−1 perpendicular to the c axis. It is found that the ionic conductivity can be optimized by increasing the number of interstitial oxygen and reducing the size of interlayer cations.
Original languageEnglish
Pages (from-to)3091-3096
Number of pages6
JournalJournal of Materials Chemistry A
Volume3
Early online date15 Dec 2014
DOIs
Publication statusPublished - 14 Feb 2015

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