Dielectric properties of proton conductor BaCe0.9Y0.1O3-.DELTA.

Abstract

Frequency dependences of the dielectric constant (e r ′ ) were investigated for the perovskite-type oxide BaCe 0.9 Y 0.1 O 3-d , which is a typical proton conductor. Numerical calculation of the frequency dependence of e r ′ clarified that the large e r ′ originated from the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. The Debye-type polarizations which originated from the dopant-vacancy associates, were depressed under wet Ar atmosphere. Therefore, it can be speculated that the proton may occur according to the following equilibrium equation:

Structural and Dielectric Investigations of Cerium Stabilized Zirconia (Zr1-xCexO2(x=0-0.05)) Nanocrystals Blended by Wet Chemical Method

“…This results in higher grain conductivity due to oxygen vacancies which execute local motions around Ce 3+ dopant giving rise to long range migrations. This type of shifting of relaxation peaks is explained by H. Yamamura et al in an earlier report, according to which the relaxation peaks at higher frequency side corresponds to defect pair such as ( ʹ − 0 •• ) and relaxation peaks at lower frequency side are due to neutral trimers such as ( ʹ − 0 •• − ʹ ) [23]. This shows that oxygen vacancy and dopants have columbic interaction, hence, depending on Ce 3+ ion concentration, the relaxation peak shifts to higher frequency region due to the variation in defect pairs.…”

Electrode Effects on Dielectric Relaxation in Oxide-Ion Conductor Ce0.7Yb0.3O2-δ Having a Fluorite-Type Structure

“…Furthermore, we have also clarified the proton-conduction mechanism of a typical proton conductor BaCe 0:9 Y 0:1 O 3À by the analysis of dielectric relaxations. 12) To clarify the origin of semicircles in the impedance spectra of oxide-ion conductors, in the present study, we carried out the numerical analysis of complex dielectricconstants for Ce 0:7 Yb 0:3 O 2À with Pt and perovskite-type oxide La 0:6 Sr 0:4 FeO 3À electrodes, which have recently been adopted as cathode materials for the SOFC system owing to the mixed conduction of electron and oxide ions. 13)…”