Article
2022

Mixed Ionic-Electronic Conductivity of the Fluorite-Type Ce1 – x – yLaxPryO2 – δ Solid Solutions under Reducing Conditions


A. I. Ivanov A. I. Ivanov , S. I. Bredikhin S. I. Bredikhin , V. V. Kharton V. V. Kharton
Russian Journal of Electrochemistry
https://doi.org/10.1134/S1023193522020045
Abstract / Full Text

Abstract—

The electrical conductivity of fluorite-type Ce1 – x – yLaxPryO2 – δ (x = 0.29–0.40, y = 0–0.14) solid solutions was studied over the oxygen partial pressure range from 10–20 to 0.5 atm at 973–1223 K. The (Сe,La)O2 – δ was shown to possess predominant anion conductivity with the oxygen ion transference numbers above 0.99 over the entire temperature range. The decreasing of the oxygen partial pressure leads to an increase in n-type electronic conduction. The data on total conductivity as a function of the oxygen partial pressure varying from 10–8 atm down to 10–20 atm was used to model the electronic and ionic defect formation and transport processes under reductive conditions. The concentrations of point defects and their diffusivities were calculated. The concentration of electrons localized at cerium cations, their mobility and, consequently, the partial n-type electronic conductivity were all found to decrease with the increasing of the dopants concentration. The oxygen-ion conductivity and the oxygen vacancy mobility both decreased with the increasing of the La3+, Pr3+, and Ce3+ cations’ total content. This behavior can be explained by the formation of point-defect clusters comprising Ln3+ and anion vacancies, which becomes more favorable with the addition of Ln3+.

Author information
  • Osipyan Institute of Solid State Physics, Russian Academy of Sciences, 142432, Chernogolovka, Moscow oblast, Russia

    A. I. Ivanov, S. I. Bredikhin & V. V. Kharton

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