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@PHDTHESIS{Karacan:1048642,
      author       = {Karacan, Cinar},
      title        = {{E}ntwicklung von nickelbasierten katalysatorbeschichteten
                      {D}iaphragmen für die alkalische {W}asserelektrolyse},
      volume       = {679},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2025-04772},
      isbn         = {978-3-95806-860-5},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {146},
      year         = {2025},
      note         = {Dissertation, RWTH Aachen University, 2025},
      abstract     = {Energy storage plays an important role for the weather
                      dependence of energy production via renewable energy power
                      plants. One way of energy storage is the electrochemical
                      production of hydrogen via water electrolysis. A well-known
                      technology is alkaline water electrolysis. The advantage of
                      alkaline water electrolysis over the acidic PEM electrolysis
                      is the use of nonplatinum metal catalysts. However, the high
                      gas impurity, which is caused by the porous diaphragms and
                      the mixing of the electrolytes, shows a big problem for the
                      dynamic operation of the electrolyzer, which is important
                      for the direct connection to renewable power plants. To
                      counter this problem, spacers are installed between the
                      electrodes to reduce gas impurity. However, this leads to
                      high ohmic losses and thus to a low power density. These
                      power losses are not competitive with the high power
                      densities of acid PEM electrolysis, which use a zerogap
                      constellation. These losses of power densities are
                      compensated by larger cell areas, but results in high system
                      costs, offsetting the advantage of non-platinum group
                      catalysts. Based on this background, this work deals with
                      the development of new electrode systems for
                      classical-alkaline electrolysis. First, a new measurement
                      protocol for alkaline single cell tests is developed to
                      ensure a reliable evaluation of these new electrode systems.
                      Then, nickelbased catalyst powders are tested via the
                      rotating disk electrode for suitability as HER catalysts for
                      the new electrode system. The most suitable HER catalyst is
                      then coated onto the Zirfon® diaphragm in the zero-gap
                      constellation via the doctor blade process and tested with
                      various parameters. The power density, long-term stability
                      and gas purity were investigated with different electrode
                      thicknesses and binder proportions. It was possible to
                      develop a catalyst coated diaphragm with a Raney nickel HER
                      catalyst for classical alkaline electrolysis in this work.
                      In this work, the best formulation was able to reduce the
                      overvoltage by 270 mV at 300 mA cm-2 compared to the
                      benchmark, which consisted of an uncoated diaphragm. This
                      reduction consisted mainly of the higher catalytic activity
                      of the Raney nickel. However, the new electrode system
                      showed lower long-term stability than the benchmark, which
                      resulted from the successive reduction in catalytic
                      activity. The gas purity tests showed that the
                      catalyst-coated diaphragm can find its application in the
                      zero-gap constellation in atmospheric electrolyzers, where a
                      partially separated electrolyte cycle prevails.},
      cin          = {ICE-2 / IET-4},
      cid          = {I:(DE-Juel1)ICE-2-20101013 / I:(DE-Juel1)IET-4-20191129},
      pnm          = {1231 - Electrochemistry for Hydrogen (POF4-123) / 1111 -
                      Effective System Transformation Pathways (POF4-111) / 1112 -
                      Societally Feasible Transformation Pathways (POF4-111)},
      pid          = {G:(DE-HGF)POF4-1231 / G:(DE-HGF)POF4-1111 /
                      G:(DE-HGF)POF4-1112},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.34734/FZJ-2025-04772},
      url          = {https://juser.fz-juelich.de/record/1048642},
}