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@PHDTHESIS{Udomsilp:844683,
      author       = {Udomsilp, David Rasnada},
      title        = {{C}harakterisierung und {O}ptimierung der {G}renzfläche
                      {E}lektrolyt/{K}athode in metallgestützten
                      {F}estelektrolyt-{B}rennstoffzellen},
      volume       = {411},
      school       = {Universiät Bochum},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2018-02068},
      isbn         = {978-3-95806-304-4},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {176 S.},
      year         = {2018},
      note         = {Universität Bochum, Diss., 2018},
      abstract     = {Metal-supported solid oxide fuel cells (MSC) offer various
                      advantages compared to full ceramic cells. Low-cost
                      materials and high mechanical ruggedness make MSCs the fuel
                      cell of choice for mobile applications, such as auxiliary
                      power units for heavy duty vehicles or range extender
                      modules for battery electric passenger cars. However,
                      MSC-specific degradation phenomena occur, as the processing
                      has to be adapted to the porous metal substrate. For
                      example, the
                      La$_{0,58}$Sr$_{0,4}$Co$_{0,2}$Fe$_{0,8}$O$_{3-\delta}$(LSCF)
                      cathode of the state-of-the-art Plansee MSC is in situ
                      activated at 850 °C,which differs considerably from the
                      established cathode sintering at 1040 °C for anode
                      supported cells. As a result, the cathode adherence on the
                      Ce$_{0.8}$Gd$_{0.2}$O$_{2-\delta}$ diffusion barrier and
                      long-term stability during operation are insufficient. The
                      aim of the present work is to increase the long-term
                      stability of the LSCF cathode by improving the adherence
                      strength of the cathode layer. Moreover, an increase of the
                      cell performance is of interest from an industrial point of
                      view, in order to lower system weight and volume. Three
                      approaches were considered: i) development of an ex situ
                      sintering procedure for complete MSCs under controlled
                      atmosphere in combination with an increased sintering
                      temperature; ii) improvement of the cathode adherence after
                      in situ activation by optimizing the activation conditions
                      or cathode raw material; and iii) implementation of
                      alternative cathode materials like
                      La$_{0,5}$8Sr$_{0,4}$CoO$_{3-\delta}$ (LSC) in order to
                      increase cell performance. Increased sintering activity and
                      adherence strength were observed by dilatometry and adhesive
                      tape test, when increasing the sintering temperature to T
                      ≥ 950 °C. Ex situ sintering of MSCs under argon
                      atmosphere caused phase decomposition of the cathode
                      material. The reversibility of this phase decomposition was
                      confirmed by ambient temperature as well as high-temperature
                      XRD. Full re-oxidation to single phase perovskite takes
                      place at T ≥ 750 °C during the heat-up and sealing
                      procedure prior to cell operation, without damaging the
                      cathode layer. Cells utilizing Ni/YSZ anode and LSCF cathode
                      sintered ex situ delivered improved cell performance of 1.4
                      A/cm$^{2}$ at 785 °C and 0.7 V. 1500 h of continuous
                      operation (300 mA/cm²,700 °C), without any degradation,
                      confirmed the long-term stability. Implementationof LSC
                      cathodes resulted in increased cell performance. 700 h of
                      operation at 300 mA/cm$^{2}$ and 700 °C did not reveal any
                      degradation of a cell consisting of Ni/YSZanode and LSC
                      cathode activated in situ at 850 °C. Promising
                      low-temperature performance of 0.8 A/cm$^{2}$ at 600 °C and
                      0.7 V was achieved by utilizing LSC cathodeon cells with
                      Ni/GDC anode. As a further development, LSC/GDC dual-phase
                      cathodes were applied using the ex situ sintering approach.
                      This cathode type not only revealed improved layer stability
                      during storage but also provided high electrochemical
                      performance of 1.3 A/cm$^{2}$ at 750 °C and 0.7 V, despite
                      nonoptimized microstructure. The overarching conclusion is
                      that cathodes sintered ex situ provide significantly
                      improved long-term stability as well as high electrochemical
                      performance during MSC operation. Optimization of the
                      microstructure of dual-phase cathodes offers further
                      potential to improve cell performance.},
      cin          = {IEK-1},
      cid          = {I:(DE-Juel1)IEK-1-20101013},
      pnm          = {135 - Fuel Cells (POF3-135) / SOFC - Solid Oxide Fuel Cell
                      (SOFC-20140602)},
      pid          = {G:(DE-HGF)POF3-135 / G:(DE-Juel1)SOFC-20140602},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/844683},
}