Anisotropic oxide ion conduction in melilite intermediate temperature electrolytes
Keenan, Philip J.
Claridge, John B.
Slater, Peter R.
Kloc, Christian Leo
White, Timothy John
Date of Issue2015
School of Materials Science and Engineering
Energy Research Institute
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.
Anisotropic oxide ion conduction
Journal of Materials Chemistry A
© 2015 The Royal Society of Chemistry. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Materials Chemistry A, The Royal Society of Chemistry. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1039/C4TA05132G].