Quantifying multi-ionic conduction through doped ceria-carbonate composite electrolyte by a current-interruption technique and product analysis

A composite electrolyte consisting of a samarium doped ceria and a binary eutectic carbonate phase is investigated in this work. It has been found that O2−/H+ conductions take place when H2 and O2 used as the reactants. The presence of CO2 in the cathode gas leads to the appearance of CO32− conduction. The overall conductivity of the composite electrolyte is measured with a current-interruption technique and the ions transferred by O2−/H+/CO32− respectively are obtained by a quantitative measurement of the reaction products, i.e. H2O and CO2. The change of the carbonate content in the composite electrolyte presents a great influence on the conductivity of each ion. According to these experimental facts, the pathways for the individual ionic conductions are proposed.

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► The current-interrupt method is used to measure the total ionic conductivity.
► The products of the single cell operation are quantitatively analyzed.
► H+, O2− and CO32− conductions in the ceria-carbonate electrolyte are proved.
► The comparative importance of the three ionic conductions is determined.
► The conduction mechanisms of H+, O2− and CO32− are proposed.