Surface chemistry of La0.6Sr0.4CoO3-δ thin films and its impact on the oxygen surface exchange resistance

Ghislain M. Rupp, Helena Téllez, John Druce, Andreas Limbeck, Tatsumi Ishihara, John Kilner, Jürgen Fleig

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    68 Citations (Scopus)

    Abstract

    The surface composition of dense La0.6Sr0.4CoO3-δ (LSC) thin film model electrodes, deposited by pulsed laser deposition at 600 °C on yttria-stabilized zirconia (100) electrolytes, was investigated by low-energy ion scattering (LEIS) and time resolved inductively coupled plasma mass spectrometry (ICP-MS). Results obtained by both methods agree qualitatively and quantitatively and provide a comprehensive picture of the surface composition and cation diffusion kinetics of LSC. The measurements revealed that freshly prepared LSC thin films already show a Sr-rich and Co-poor termination layer (80% Sr surface coverage). This Sr-rich surface layer was proven to be an equilibrium property of LSC as it forms again at elevated temperatures after removal. The kinetics of this surface reconstruction is surprisingly fast (<1 h at 550 °C) and indicates high Sr mobility in LSC. Electrochemical Impedance Spectroscopy (EIS) measurements at 400 °C revealed the detrimental effect of this surface layer on the oxygen surface exchange and suggest that higher Co concentrations in the termination layer facilitate the oxygen exchange reaction.

    Original languageEnglish
    Pages (from-to)22759-22769
    Number of pages11
    JournalJournal of Materials Chemistry A
    Volume3
    Issue number45
    DOIs
    Publication statusPublished - 2015

    All Science Journal Classification (ASJC) codes

    • Chemistry(all)
    • Renewable Energy, Sustainability and the Environment
    • Materials Science(all)

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