Electrochemical Impedance Studies of SOFC Cathodes

Johan Hjelm, Martin Søgaard, Marie Wandel, Mogens Bjerg Mogensen, Mohan Menon, Anke Hagen

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    Abstract

    Mixed ion- and electron-conducting composite electrodes consisting of doped ceria and perovskite have been studied by electrochemical impedance spectroscopy (EIS) at different temperatures and oxygen partial pressures. This paper aims to describe the different contributions to the polarisation impedance of the cathode at intermediate operating temperatures. The perovskite is of the La-Sr-Co-Fe type. The EIS response of symmetrical cells with a thick (similar to 200 mu m) gadolinia doped ceria electrolyte was compared with the impedance contribution of the cathode of a full anode supported cell. The full cells had a Ni-YSZ anode and anode support, a thin YSZ electrolyte, and a CGO barrier layer. The symmetric and full cell cathode responses were compared at open-circuit voltage. Humidified hydrogen was used as the fuel in the full cell measurements. Differential analysis of the impedance data was used to identify frequency ranges where changes occur upon degradation and oxygen partial pressure variations.
    Original languageEnglish
    JournalE C S Transactions
    Volume7
    Issue number1
    Pages (from-to)1261-1270
    ISSN1938-5862
    DOIs
    Publication statusPublished - 2007
    Event10th International symposium on solid oxide fuel cells - Nara New Public Hall, Nara, Japan
    Duration: 3 Jun 20078 Jun 2007
    Conference number: 10

    Conference

    Conference10th International symposium on solid oxide fuel cells
    Number10
    LocationNara New Public Hall
    CountryJapan
    CityNara
    Period03/06/200708/06/2007

    Bibliographical note

    Copyright The Electrochemical Society, Inc. [2007]. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS).

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