TY  - JOUR
AU  - An, Tao
AU  - Baikie, Tom
AU  - Orera, Alodia
AU  - Piltz, Ross O.
AU  - Meven, Martin
AU  - Slater, Peter R.
AU  - Wei, Jun
AU  - Sanjuán, María L.
AU  - White, T. J.
TI  - Interstitial Oxide Ion Distribution and Transport Mechanism in Aluminum-Doped Neodymium Silicate Apatite Electrolytes
JO  - Journal of the American Chemical Society
VL  - 138
IS  - 13
SN  - 1520-5126
CY  - Washington, DC
PB  - American Chemical Society
M1  - FZJ-2016-06937
SP  - 4468 - 4483
PY  - 2016
AB  - Rare earth silicate apatites are one-dimensional channel structures that show potential as electrolytes for solid oxide fuel cells (SOFC) due to their high ionic conductivity at intermediate temperatures (500–700 °C). This advantageous property can be attributed to the presence of both interstitial oxygen and cation vacancies, that create diffusion paths which computational studies suggest are less tortuous and have lower activation energies for migration than in stoichiometric compounds. In this work, neutron diffraction of Nd(28+x)/3AlxSi6–xO26 (0 ≤ x ≤ 1.5) single crystals identified the locations of oxygen interstitials, and allowed the deduction of a dual-path conduction mechanism that is a natural extension of the single-path sinusoidal channel trajectory arrived at through computation. This discovery provides the most thorough understanding of the O2– transport mechanism along the channels to date, clarifies the mode of interchannel motion, and presents a complete picture of O2– percolation through apatite. Previously reported crystallographic and conductivity measurements are re-examined in the light of these new findings.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000373748000034
C6  - pmid:27015162
DO  - DOI:10.1021/jacs.5b13409
UR  - https://juser.fz-juelich.de/record/824328
ER  -