Article ID Journal Published Year Pages File Type
1297907 Solid State Ionics 2009 12 Pages PDF
Abstract

Chemical diffusivity of a mixed ionic–electronic conductor compound is often measured by monitoring the relaxation of electrical conductivity with time under a component's chemical potential gradient. Conductivity relaxations were systematically examined on undoped polycrystal BaTiO3, acceptor-doped polycrystal BaTiO3, donor-doped polycrystal BaTiO3, and undoped single crystal TiO2 upon oxidation and reduction, and on proton-conducting, acceptor-doped polycrystal SrCeO3 and BaCeO3 upon oxidation/reduction or hydration/dehydration at elevated temperatures. It has been found that there are three patterns of relaxation: single-fold (single relaxation time) monotonic, twofold (two relaxation times) monotonic and twofold non-monotonic relaxation. The inner working for each pattern is discussed and a general solution to the relaxations is presented in closed form, together with the chemical diffusivities as evaluated thereby.

Related Topics
Physical Sciences and Engineering Chemistry Electrochemistry
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