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@INPROCEEDINGS{Sohn:863568,
      author       = {Sohn, Yoo Jung and Lenser, Christian and Jeong, Hyeondeok
                      and Guillon, Olivier and Menzler, Norbert H.},
      title        = {{I}nterdiffusion between gadolinium-doped ceria and
                      yttria-stabilized zirconia and its impact on cell
                      performance},
      reportid     = {FZJ-2019-03607},
      year         = {2019},
      abstract     = {Advantageous aspects of gadolinium doped ceria (GDC) as an
                      anode layer in anode-supported solid oxide fuel cells are
                      well known regarding its high electrochemical performance
                      and improved tolerance against sulfur poisoning and coking
                      [1]. A high-sintering temperature of 1400 °C is necessary
                      to fabricate a dense electrolyte, and to achieve the desired
                      shrinkage of the anode substrate. An anode-supported cell
                      with a Ni-GDC anode and a yttria-stabilized zirconia (YSZ)
                      electrolyte showed a strongly decreased performance during
                      cell testing compared to cells using Ni-YSZ as the anode.
                      Hence, the interdiffusion of GDC-YSZ has been studied in
                      detail to better understand its physical properties. Powders
                      of 20GDC and 8YSZ have been mixed in equal weight ratio, and
                      sintered at the same conditions as for the anode-supported
                      cells to examine the sintering behavior of the intermixing
                      phase. Ex-situ as well as in-situ high-temperature X-ray
                      diffraction (XRD) was carried out up to 1400 °C to observe
                      the intermixing of GDC-YSZ as a function of temperature.
                      Pawley refinements and Rietveld analysis were performed on
                      the powder XRD data to calculate the lattice parameters and
                      to quantify the intermixing phases, respectively. Since the
                      lattice parameters of the GDC-YSZ solid solution follows
                      Vegard’s rule [2], the calculated lattice parameters were
                      used to determine the stoichiometry of the intermixing
                      phases. Using these constraints, corresponding Rietveld
                      analysis were undertaken to quantify GDC, YSZ and GDC-YSZ
                      intermixing phases as a function of temperature. A complete
                      interdiffusion of GDC-YSZ already took place at 1300 °C,
                      which suggests a formation of this mixed layer during cell
                      sintering process at the interface of anode layer and
                      electrolyte. Besides, we observed that the presence of NiO
                      enhanced the diffusion kinetics of GDC and YSZ. X-ray
                      photoelectron spectroscopy, 4-point conductivity and
                      thermo-gravimetric analysis were conducted to investigate
                      the reducibility, ionic and electronic conductivity of the
                      GDC-YSZ mixed phase in air and under reducing conditions
                      [3]. Impedance spectroscopy and microstructure analysis
                      reveals an increase in the ohmic resistance of the cell due
                      to the GDC-YSZ intermixing, and a strong increase in anode
                      polarization which is probably due to the porosity at the
                      interface caused by the difference in diffusion coefficients
                      of Ce4+ and Zr4+ (Kirkendall effect).},
      month         = {Jun},
      date          = {2019-06-16},
      organization  = {22nd International Conference on Solid
                       State Ionics, PyeongChang (Republic of
                       Korea), 16 Jun 2019 - 21 Jun 2019},
      subtyp        = {After Call},
      cin          = {IEK-1 / JARA-ENERGY},
      cid          = {I:(DE-Juel1)IEK-1-20101013 / $I:(DE-82)080011_20140620$},
      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)6},
      url          = {https://juser.fz-juelich.de/record/863568},
}