High-temperature protonic conduction in LaFeO3-SrFeO 3-δ-SrZrO3 solid solutions

Atsushi Unemoto, Atsushi Kaimai, Kazuhisa Sato, Naoto Kitamura, Keiji Yashiro, Hiroshige Matsumoto, Junichiro Mizusaki, Koji Amezawa, Tatsuya Kawada

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)

    Abstract

    The electrical conductivity of a pseudoternary system, consisting of LaFeO3-SrFeO3-δ-SrZrO3, { La 0.05 (1-x) Sr0.95+0.05x } (Zr0.95 Fe 0.05)O3-δ (x=0-0.5), was evaluated both in oxygen and hydrogen containing environments by a two-probe ac technique. Correlations of oxygen partial pressure, water vapor pressure, and composition dependences of the electrical conductivities with possible defect concentrations are examined by a semiquantitatively derived Brouwer diagram. In oxygen for x below 0.25, major carriers were identified to be oxide ions and electron holes, while for x=0.5 they were a mixture of oxide ions, electron holes, and protons. In a hydrogen containing environment, the oxides with compositions for x=0.25 and 0.5 were unstable. Thus, the electrical conductivity was analyzed in detail for x=0.1. It was found that the oxide conducts protons significantly at temperatures below 1273 K, which was evidenced by the isotope effect of hydrogen and deuteron on the electrical conductivity. The electrical conductivity of the oxide increased with decreasing oxygen partial pressure due to the variation of oxygen nonstoichiometry, accompanied by partial reduction of Fe ions in the oxide. The transport number of proton increased as the oxygen partial pressure decreased. The gas partial pressure and the composition dependences of the electrical conductivity and the transport number of proton could be well explained by the conceptual Brouwer diagram proposed in this work.

    Original languageEnglish
    JournalJournal of the Electrochemical Society
    Volume158
    Issue number2
    DOIs
    Publication statusPublished - Jan 5 2011

    All Science Journal Classification (ASJC) codes

    • Electronic, Optical and Magnetic Materials
    • Renewable Energy, Sustainability and the Environment
    • Surfaces, Coatings and Films
    • Electrochemistry
    • Materials Chemistry

    Fingerprint Dive into the research topics of 'High-temperature protonic conduction in LaFeO<sub>3</sub>-SrFeO <sub>3-δ</sub>-SrZrO<sub>3</sub> solid solutions'. Together they form a unique fingerprint.

    Cite this