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Multiphase-field simulation of coarsening in an SOFC-anode under surface and grain boundary self-diffusion

Thursday (27.09.2018)
12:30 - 12:45 S1/01 - A2
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Solide oxide fuel cells (SOFCs) enable to generate electric energy from fuels such as fossile fuels or hydrogen. SOFCs achieve an excellent efficiency of the energy conversion process compared to conventional techniques. However, a remaining technological challenge is to obtain a long lifetime of an SOFC-device. How and up to which extent several microstructural modification processes such as coarsening contribute to the loss in SOFC performance during operation remains an open question.

We analyze the microstructural evolution of an Ni-YSZ SOFC-anode under operating conditions utilizing a multiphase-field model in combination with a grand-chemical formulation to incorporate diffusional transport processes. The model was used to simulate a polycrystalline three-phase microstructure undergoing surface and grain-boundary self-diffusion of Nickel and concomitant grain-growth therein. A validation of the model was performed by simulations of thermal-grooving under surface diffusion in comparison with analytical theories. We discuss the influence of several input parameters such as grain size on the coarsening process of the SOFC-anode. The resulting microstructures are analyzed regarding their effective electric conductivity (tortuosity), triple-phase boundary-length (TPBL) and change in particle size.

Paul Hoffrogge
Karlsruhe University of Applied Sciences
Additional Authors:
  • Dr. Daniel Schneider
    Karlsruhe Institute of Technology (KIT)
  • Prof. Dr. Britta Nestler
    Karlsruhe Institute of Technology (KIT)
  • Patricia Haremski
    Karlsruhe Institute of Technology (KIT)
  • Dr. Matthias Wieler
    Robert Bosch GmbH
  • Dr. Piero Lupetin
    Robert Bosch GmbH