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@PHDTHESIS{Usler:1013964,
      author       = {Usler, Adrian Leonhard},
      othercontributors = {De Souza, Roger Armand and Lüchow, Arne},
      title        = {{I}nvestigation of charge and mass transport in
                      ion-conducting solids by means of continuum and atomistic
                      simulations},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2025-05829},
      pages        = {1 Online-Ressource : Illustrationen},
      year         = {2025},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, RWTH Aachen University, 2025},
      abstract     = {A rational design of electroceramics requires a detailed
                      understanding of defect transport, both within the bulk of
                      the crystalline grains and across the grain boundaries.
                      These two overarching topics are approached in this work
                      from a computational perspective. The first part of this
                      work is dedicated to the common practice of predicting
                      ion-transport properties by extracting a diffusion
                      coefficient from Molecular Dynamcis simulations. This
                      practice is subjected to methodological scrutiny with regard
                      to the statistical error in the simulation outcome. The
                      dependence of the statistical error on simulation parameters
                      is analysed by means of kinetic Monte Carlo (kMC)
                      simulations. On the basis of the results, a mathematical
                      expression is introduced that allows for a simple assessment
                      of the statistical error from a single simulation. In the
                      following parts of this work, space-charge phenomena at
                      grain boundaries in solid electrolytes are studied by means
                      of continuum simulations. In the second part, grain-boundary
                      impedance is calculated from drift–diffusion simulations
                      of different space-charge models. Frozen-in profiles of
                      accumulated acceptor cations at the grain boundaries are
                      modelled in the scope of the restricted-equilibrium model.
                      It is analysed how this feature translates into systematic
                      errors in the determination of the space-charge potential
                      from impedance data. In the third part, space-charge layers
                      are approached from a combined atomistic and continuum
                      perspective. First, segregation energies of oxygen vacancies
                      and acceptor cations are obtained from Molecular Statics
                      simulations on a model grain boundary. It is then studied on
                      the continuum level how the variety of segregation energies
                      affects the temperature dependence of the space-charge
                      potential, and to which degree space-charge models may be
                      simplified. In the fourth part, grain-boundary impedance is
                      obtained from drift–diffusion simulations of space-charge
                      layers in a concentrated solid solution. The influence of
                      defect–defect simulations on the configuration of the
                      space-charge layers is modelled in the scope of the
                      Poisson–Cahn model. Lastly, in the fifth part, the effects
                      of a transition between different bulk defect-chemical
                      regimes on the temperature dependence of the space-charge
                      potential are analysed, and it is discussed how the
                      differences between these regimes lead to disparities
                      between experimental data gathered in different temperature
                      ranges.},
      cin          = {153110 / 150000},
      ddc          = {540},
      cid          = {$I:(DE-82)153110_20140620$ / $I:(DE-82)150000_20140620$},
      pnm          = {DFG project G:(GEPRIS)274005202 - SPP 1959: Manipulation of
                      matter controlled by electric and magnetic fields: Towards
                      novel synthesis and processing routes of inorganic materials
                      (274005202)},
      pid          = {G:(GEPRIS)274005202},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2025-05829},
      url          = {https://publications.rwth-aachen.de/record/1013964},
}