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@INPROCEEDINGS{Khan:1009360,
author = {Khan, Muhammad Shirjeel and Menzler, Norbert H.},
collaboration = {Lenser, Christian and Dellen, Christian and Sebold, Doris
and Sohn, Yoo Jung and Wessel, Egbert},
title = {{N}ew insights into the fuel electrode degradation during
solid oxide cells operation},
reportid = {FZJ-2023-02776},
year = {2023},
abstract = {The electrochemical performance of solid oxide cermet
electrodes is expected to improve with increased ionic
conductivity of the ion-conducting phase. We explored this
concept coupled with the effects of microstructural and
compositional changes in nickel-yttria-stabilized zirconia
(Ni-YSZ) and nickel-scandia-ceria-stabilized zirconia
(Ni-ScCeSZ) on their electrochemical performance. The
electrodes with 56:44 (NiO:YSZ or ScCeSZ) ratio and
different thicknesses were symmetrically screen printed on
YSZ pellets and sintered at 1400 °C for 5 h. The
electrochemical impedance spectroscopy (EIS) for the
prepared cells was then evaluated between 800-600 °C in
$Ar-3\%H2.$ It was found that the area-specific resistance
(ASR) for Ni-ScCeSZ was much higher compared to the
conventional Ni-YSZ under these conditions, even though the
ionic-conductivity of ScCeSZ is greater than YSZ. Increasing
the initial NiO content in NiO-ScCeSZ from 56 wt. $\%$ to 65
wt. $\%$ also did not improve its electrochemical
performance relative to Ni-YSZ. The cells were then analyzed
using scanning electron microscopy (SEM), which showed the
formation of cracks and a contact loss between Ni and ScCeSZ
particles after EIS test. No such cracking was observed in
these cells before EIS test, demonstrating that the contact
loss is associated with the reduction of Ni. For the
conventional Ni-YSZ, all the particles were still intact,
before and after EIS test, illustrating the presence of
large number of triple phase boundaries and hence a better
performance than Ni-ScCeSZ. The X-ray diffraction (XRD)
analysis did not show any new phase formation or changes in
the crystal structures of Ni(O) and ScCeSZ. The transmission
electron microscopy (TEM), however, showed the presence of
scandium (Sc)-rich phase at the NiO grain boundaries after
sintering and provided some interesting insights into the
diffusion-related degradation phenomenon responsible for the
contact loss between Ni and ScCeSZ particles.},
month = {Jul},
date = {2023-07-02},
organization = {XVIII Conference $\&$ Exhibition of
the European Ceramic Society, Lyon
(France), 2 Jul 2023 - 6 Jul 2023},
subtyp = {Plenary/Keynote},
cin = {IEK-1 / IEK-2},
cid = {I:(DE-Juel1)IEK-1-20101013 / I:(DE-Juel1)IEK-2-20101013},
pnm = {1231 - Electrochemistry for Hydrogen (POF4-123) / SOFC -
Solid Oxide Fuel Cell (SOFC-20140602)},
pid = {G:(DE-HGF)POF4-1231 / G:(DE-Juel1)SOFC-20140602},
typ = {PUB:(DE-HGF)6},
url = {https://juser.fz-juelich.de/record/1009360},
}