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@PHDTHESIS{Bischof:874446,
author = {Bischof, Cornelia},
title = {{L}eistungssteigerung metallgestützter
{F}estelektrolyt-{B}rennstoffzellen ({MSC}s) durch gezielte
{O}ptimierungen des {A}noden / {E}lektrolytverbunds},
volume = {487},
school = {Diss. Bochum},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2020-01447},
isbn = {978-3-95806-455-3},
series = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
Umwelt / Energy $\&$ Environment},
pages = {X, 176},
year = {2020},
note = {Dissertation, Diss. Bochum, 2019},
abstract = {This work addressed the perfomance increase of
metal-supported solid oxide fuel cells (MSCs) by
optimization of the anode/electrolyte interface. Properties
of the anode are strongly influenced by process parameters
of the used screen printing process, a powder-based process.
In comparison, properties of the electrolyte are influenced
by process parameters of a specific physical vapor
deposition (PVD) method. In this work, both processes were
adapted to increase cell performance by improving cell
design, cell layer thicknesses and microstructures. The goal
of this work was the increase of the electrochemically
active surface and the decrease of polarization resistances
of the anode functional layer and ohmic resistances of the
electrolyte. In a first step, cells developed in the PhD
thesis of Rojek-Wöckner were reproduced and acted as a
reference for further development. In a second step, the
electrochemically active surface of the anode functional
layer was raised. By reducing the sintering temperature,
reduced coarsening of the microstructure resulted during
processing. However, this was found to be detrimental due to
undesired side effects. At low anode thicknesses, mechanical
stability of the layered composite anode suffered because of
low sintering between the particles. In addition, at high
anode functional layer thicknesses, gas permeability
suffered because of a both thick and fine-pored layer.
Availability of fuel gas in the layered composite anode
decreased, leading to increased anode polarization
resistance. By increasing the layer thickness, a positive
side effect appeared by lowering the surface roughness. A
low surface roughness is a requirement for a gas-tight
PVD-thin film electrolyte. Therefore, this concept with a
thicker anode functional layer was used to successfully
implement a cell design with a 2 μm thick PVD-electrolyte.
This can be taken as starting point for future improvement
of a 2 μm thin-film electrolyte. By increasing the
sintering temperature of the functional layer in this design
as well, stability and permeability of the layered composite
anode were increased. Still, signs of gas diffusion
limitation at high current densities became visible. To
overcome this, a further improved cell design was
implemented. An electrochemically inactive Ni/YSZ-interlayer
was exchanged by an electrochemically active Ni/GDC-layer.
Compared to the reference cell concept of Rojek-Wöckner,
the improved cell design with a double-layered Ni/GDC-anode
functional layer enabled a performance increase from 1,29
A/cm$^{2}$ to 1,79 A/cm$^{2}$ and therefore by 38\%. The
active surface and the permeability of the layered composite
anode were increased. Moreover, mechanical stability and
reproducibility were enhanced. Furthermore, the cell showed
lower deflection after processing easing the handling of the
cell during next processing steps like stack assembling
[...]},
cin = {IEK-1},
cid = {I:(DE-Juel1)IEK-1-20101013},
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)3 / PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/874446},
}