Isothermal charge transport properties of La0.1Sr0.9Co0.8Fe0.2O3-δ by blocking cell method

Abstract

In this work, we investigated charge transport properties of La0.1Sr0.9Co0.8Fe0.2O3-δ (LSCF1982) by a blocking cell experiment in isothermal conditions in 800-950° C range. By measuring the ionic charge of transport (αi∗ ) vs. oxygen partial pressure (pO2), the cross-effect between ionic and electronic flows were investigated. The values of αi∗ were found to be non-zero with a magnitude of 0.43-1.15 in 800-950° C range, indicating that even in the absence of a direct cause of electron flow a significant number of electrons are dragged by the cations. By constructing an Onsager matrix, the values of Onsager transport coefficients were extracted. It was observed that the Onsager coefficients related with the cross-effect (Lie = Lei) have nearly of the same order of magnitude that of the Onsager coefficient for ionic flow (Lii) and therefore cannot be ignored. The values of partial ionic conductivity were calculated from Onsager matrix and which showed an exponential increase (ρO2- α pO2m, m = 1/2) with increasing pO2 and temperature at 800° C but less dependence on pO2 at the higher temperatures. © 2017 The Electrochemical Society.