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Analysis of Electrolyte Polarization in Polycrystalline Sodium β‐Alumina by a Complex Admittance Method
Author(s) -
JAKUBOWSKI W.,
WHITMORE D. H.
Publication year - 1979
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1979.tb19084.x
Subject(s) - electrolyte , arrhenius equation , grain boundary , crystallite , admittance , isothermal process , materials science , polarization (electrochemistry) , microstructure , analytical chemistry (journal) , ion , activation energy , mineralogy , electrode , composite material , chemistry , thermodynamics , metallurgy , electrical impedance , electrical engineering , physics , organic chemistry , chromatography , engineering
The polarization behavior of lithia‐stabilized sodium β‐alumina in the form of polycrystalline pressed and sintered specimens was studied at 100° to 400°C by observing the isothermal values of the complex admittance from ≊5 Hz to 500 kHz. Analyzing these data in the complex admittance plane in terms of an equivalent circuit for the system made it possible, when ion‐blocking electrodes were used, to distinguish the separate contributions of the grain boundaries and the bulk crystals to the total electrolyte resistance. These results gave activation energies of 0.32 to 0.41 eV for the grain‐boundary resistance and 0.11 to 0.14 eV for the bulk resistance. The prefactors in the Arrhenius expressions for these resistances appeared to be more sensitive to factors such as specimen composition, microstructure, and specimen preparation conditions than are the activation energies.