Ionic conduction due to oxygen diffusion in La0.8Sr0.2GaO3−δ electrolyte

Abstract

Dielectric and dc measurements have been carried out on La0.8Sr0.2GaO3−δ, which has a high potential for the electrolyte material in a solid oxide fuel cell, so as to elucidate the correlation between O2− diffusion and electric conduction. A dielectric relaxation shows up in loss tangent. The relative relation of activation energies as to dielectric relaxation and dc conduction suggests the ionic conduction due to O2− diffusion assisted by free single oxygen vacancies taking place. The change of dc conductive behavior associated with attenuation of dielectric relaxation around 950 K indicates that another type of O2− diffusion dominates the ionic conduction at high temperature.

Dense La0.9Sr0.1Ga0.8Mg0.2O2.85 electrolyte for IT-SOFC's: Sintering study and electrochemical characterization

“…In the present case (LSGM12),˛R does not vary significantly in the temperature range (200-400 • C) where the inductive component permits the distinction between the intragrain and intergrain contributions. This was also observed by Iguchi et al [42] in their work on La 0.8 Sr 0.2 GaO 3−ı . As a result, we cannot assume that the total resistivity is equal to the intragrain resistivity in the high temperature range (>400 • C).…”

“…In the case of the ionic conductor, activation energies E M and E D are related to f tan ı and tan ı max according to the next equations [42,55,57,58]:…”

Electrical conduction and dielectric relaxation process in Ce0.8Y0.2O1.9 electrolyte system

“…The oxide ion diffusion involves various thermal activation processes and the activation energy estimated from the electrical conductivity does not separate such processes and the obtained information is insufficient to estimate the value of E M and E O . Temperature dependence of the dielectric relaxation process provide the value of E M and E O , and this procedure has been used in ion conducting oxide systems and polaronic conductions in strongly correlated electrons system [8][9][10][11][12][13][14]. The resonance frequency of the relaxation process due to O 2− movement within the bulk and the grain boundary are different.…”

Dielectric and electrical properties of gadolinia doped ceria

“…6. According to previous reports [7,13], the fact that this spectrum contains two relaxations peaks is important evidence for relaxations due to the ionic transport process of grain and grain boundary for CGO. The results can be confirmed by the exhibition of two conduction components in the complex impedance spectra.…”

“…Dielectric relaxations due to ionic displacement induced by the migration of oxygen vacancies have been reported in some oxygen ionic conductors [7,8]. The study of dielectric properties present the valuable information on the behavior of localized charge carriers that lead to high ionic conduction.…”