Oxygen Migration in Dense Spark Plasma Sintered Aluminum-Doped Neodymium Silicate Apatite Electrolytes
Felix Shin, J.
Slater, Peter R.
White, Timothy John
Date of Issue2013
School of Materials Science and Engineering
Energy Research Institute
Neodymium silicate apatites are promising intermediate temperature (500°C–700°C) electrolytes for solid oxide fuel cells. The introduction of Al promotes isotropic percolation of O2−, and at low levels (0.83–2.0 wt% Al) enhances bulk conductivity. To better understand the effect of Al-doping on intrinsic conductivity, and the impact of grain boundaries on the transport, dense Nd9.33+x/3AlxSi6−xO26 (0 ≤ x ≤ 2) pellets were prepared by spark plasma sintering. Phase purity of the products was established by powder X-ray diffraction and the microstructure examined by scanning electron microscopy. The ionic conductivity measured by AC impedance spectroscopy for the spark plasma sintered ceramics were compared with transport in single crystals of similar composition. Intermediate Al-doping (0.5 ≤ x ≤ 1.5) delivered superior overall conductivity for both the polycrystalline and single crystal specimens.
Journal of the American Ceramic Society
© 2013 The American Ceramic Society. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of the American Ceramic Society, The American Ceramic Society. 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/10.1111/jace.12489].