WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Institution Author: search.filters.institutionAuthor.Akkurt, SedatPublisher: search.filters.publisher.Springer

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  • Article
    Citation - WoS: 14
    Citation - Scopus: 15
    Electrochemical Performance of La0.6sr0.4co0.2fe0.8o3-Ce0.9gd0.1o2 Composite Sofc Cathodes Fabricated by Electrocatalyst And/Or Electrocatalyst-Ionic Conductor Infiltration
    (Springer, 2019) Sındıraç, Can; Büyükaksoy, Aligül; Akkurt, Sedat
    Infiltration of electrocatalyst precursor solutions into previously sintered porous ionic conductor scaffolds has been used recently as an alternative method to the conventional co-sintering route to fabricate electrocatalyst-ionic conductor composites for solid oxide fuel cell (SOFC) cathode applications. However, the aqueous nitrate solutions generally used to perform the infiltration process results in electrocatalyst precipitates that are disconnected from each other, yielding poor electrode performance. In this work, polymeric electrocatalyst (La0.6Sr0.4Co0.2Fe0.8O3-LSCF) precursors that produce interconnected thin films upon heat treatment were used to infiltrate porous ionic conductor Ce0.9Gd0.1O2-delta (GDC) scaffolds to overcome these issues. In addition, for the first time in the literature, a mixture of LSCF and GDC polymeric precursors, which would yield LSCF-GDC nanocomposite coatings on the grains of the porous GDC scaffold were used as the infiltration solution. Thus, further enhancement of the electrocatalyst/ionic conductor interfacial area and achievement of improved electrode performance was aimed. As a result of the optimization studies, the lowest measured area specific polarization resistance (ASR(cathode)) values of 0.47 and 0.73 omega.cm(2) were obtained for polymeric LSCF+GDC and LSCF precursor infiltrations respectively at 700 degrees C, in air. In addition, LSCF+GDC infiltration yielded electrodes with much improved long-term stability in comparison to those obtained by LSCF infiltration. [GRAPHICS] .
  • Article
    Citation - WoS: 15
    Citation - Scopus: 16
    Fabrication of Lscf and Lscf-Gdc Nanocomposite Thin Films Using Polymeric Precursors
    (Springer, 2020) Sındıraç, Can; Ahsen, Ali; Öztürk, Osman; Akkurt, Sedat; Birss, Viola, I; Büyükaksoy, Aligül
    La1-xSrxCoyFe1-yO3 (LSCF) and LSCF-gadolinia-doped ceria (LSCF-GDC) composites are used as solid oxide fuel cell (SOFC) cathodes. In the present study, to maximize the LSCF/gas and LSCF/GDC interfacial area and thus enhance the performance, we fabricated both single-phase LSCF and composite LSCF-GDC thin-film electrodes using a facile and cost-effective polymeric precursor technique. This method involves molecular level mixing of cations in solution form and results in average particle sizes of ca. 72 nm and 60 nm upon annealing at 700 degrees C, respectively. For LSCF, electrochemical impedance spectroscopy measurements indicate very low electrode polarization resistances of ca. 0.6 omega cm(2) per electrode at 600 degrees C. However, the addition of GDC results in poorer electrochemical activity but better microstructural and electrochemical stability, all at 600 degrees C. Surface analysis revealed that Fe surface segregation occurs in the single-phase LSCF, while predominantly Co segregation is observed at the LSCF-GDC composite electrode surface.