% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Beez:844630,
      author       = {Beez, Alexander},
      title        = {{M}echanismen der chrombasierten {D}egradation von
                      metallgestützten {F}estoxid-{B}rennstoffzellen},
      volume       = {413},
      school       = {Universität Bochum},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek Verlag},
      reportid     = {FZJ-2018-02029},
      isbn         = {978-3-95806-306-8},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {144 S.},
      year         = {2018},
      note         = {Universität Bochum, Diss., 2018},
      abstract     = {The aim of the present work is the investigation of the
                      chromium degradation of metal supported solid oxide fuel
                      cells (MSC). The starting point is the MSC concept of
                      Plansee SE which utilizes a
                      La$_{0.58}$Sr$_{0.40}$Co$_{0.20}$Fe$_{0.80}$O$_{3-\delta}$
                      (LSCF) cathode. From the results of three work packages,
                      conclusions are drawn how chromium degradation influences a
                      MSC cathode and if there is a possibility to prevent this
                      interaction. Using thin-film samples, strontium segregation,
                      a key process of chromium degradation, is systematically
                      investigated. For the first time a quantitative comparison
                      between LSCF and
                      La$_{0.58}$Sr$_{0.40}$Co$_{1.00}$O$_{3-\delta}$ (LSC)
                      cathode material using ICP-MS is conducted. The combination
                      of imaging (SEM) and spectroscopic (XPS) methods gives
                      strong evidence that the strontium segregation depends on
                      the thermal treatment of the sample and that it is stronger
                      on cobalt rich LSC compared to LSCF. Moreover, methods for
                      accelerated testing have been developed to poison samples
                      with porous cathode layers reproducibly. Such methods enable
                      a quick comparison of different cathodes before using them
                      in a stack test. While the poisoning via gas phases proved
                      to be poorly reproducible, the desired effect could be
                      achieved with solid state poisoning. It can be shown that
                      both poisoning techniques have the same influence on the
                      impedance spectra of poisoned cells. The third work package
                      deals with the chromium related degradation on stack level
                      and its dependence on the oxygen partial pressure. Depending
                      on the operation conditions, the deposition of a chromium
                      containing phase can be triggered at the interface between
                      the LSCF cathode and the gadolinium doped ceria diffusion
                      barrier when using an LSCF cathode. This must be prevented.
                      The combined results of all three work packages allow the
                      following conclusions: (i) a low operation temperature is
                      helpful to slow down the strontium segregation. (ii) with
                      the solid state poisoning, a method for systematic and
                      reproducible poisoning of single cells is available. With
                      this, different stages of chromium poisoning can be
                      simulated in short time.(iii) a future MSC stack design must
                      be geared to avoid gradients in oxygen partial
                      pressurethroughout the cathode layer. Otherwise, not only
                      the chromium degradation but also the intrinsic degradation
                      of the LSCF cathode is enhanced. (iv) the most effective way
                      to protect the cathode from chromium poisoning is the use of
                      a dense interconnect coating.},
      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/844630},
}