AUTHOR=Ohta Shingo , Kihira Yuki , Asaoka Takahiko 

TITLE=Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

JOURNAL=Frontiers in Energy Research

VOLUME=4

YEAR=2016

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2016.00030

DOI=10.3389/fenrg.2016.00030

ISSN=2296-598X

ABSTRACT=<p>Garnet-like oxides having the formula Li<sub>7+<italic>X</italic>−<italic>Y</italic></sub>La<sub>3−<italic>X</italic></sub>A<italic><sub>X</sub></italic>Zr<sub>2−<italic>Y</italic></sub>Nb<italic><sub>Y</sub></italic>O<sub>12</sub> (A = Sr or Ca) were synthesized using a solid-state reaction, and their bulk and grain boundary resistivities were assessed by AC impedance measurements. A difference in grain boundary resistivity was identified between Sr and Ca materials, and so the grain boundaries were examined using electron probe microanalysis (EPMA). The difference in the grain boundary resistivities was attributed to the core–shell structure of the Sr-substituted samples. In contrast, the Ca-substituted materials exhibited accumulations of impurities at the grain boundaries.</p>