The Effects of Excess Sodium and Sintering Parameters on Ionic Conductivity of Zinc Stabilized β"-Alumina
Date
2015-04
Authors
Journal Title
Journal ISSN
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Publisher
New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.
Abstract
Sodium β”-alumina is used in batteries due to its high ionic conductivity. This
work studied the effect of excess sodium on the grain size, sintering behavior, and ionic
conductivity of zinc stabilized β”-alumina. Two compositions, each with varying
amounts of excess sodium (molar Na/Al = 0.01 & 0.02), were synthesized and sintered at
varying temperatures and times (1610 °C, 1625 °C and 1640 °C; 30 minutes and 1 hour).
It was found that grain size and density had the largest influence on ionic resistivity in the
materials and that the presence of increased sodium in the composition did not aid in
sintering or decrease ionic resistivity.
Which factors affect AC impedance spectroscopy, used to measure ionic
conductivity in these materials, is not fully understood. The effects of sample thickness
and electrode material were evaluated to determine the repeatability of data across these
parameters. A connection between these factors was established. Resistivity was
determined to be independent of sample thickness; although thinner samples exhibited
greater uncertainty in collected data. Additionally, it was determined that of the choice of
electrode material did influence collected data. Resistivity and activation energy for
samples measured using gold and fluxed platinum electrode could be directly compared
to each other, whereas the data collected using unfluxed platinum and carbon electrodes
could not; showing that electrode material did affect impedance spectroscopy
measurements.
Description
Advisory committee members: Alastair Cormack, Scott Misture. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Ceramic Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis