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1 Department of Energy Conversion and Storage, Technical University of Denmark 2 Ceramic Engineering & Science, Department of Energy Conversion and Storage, Technical University of Denmark 3 Danish Technological Institute 4 Risø National Laboratory for Sustainable Energy, Technical University of Denmark 5 Linköping University 6 Danish Technological Institute
Gadolinia-doped ceria (GDC) thin films are deposited by reactive magnetron sputtering in an industrial-scale setup and implemented as barrier layers between the cathode and electrolyte in metal-based solid oxide fuel cells consisting of a metal support, an electrolyte of ZrO2 co-doped with Sc2O3 and Y2O3 (ScYSZ) and a Sr-doped lanthanum cobalt oxide cathode. In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness and adatom mobility is studied. The adatom mobility is varied by tuning the deposition temperature and substrate bias voltage. A GDC layer thickness of 0.6 μm is found to effectively block Sr diffusion when bias voltage and deposition temperature is tuned to promote dense coatings. The adatom mobility has a large influence on the film density. Low temperature and bias voltage result in underdense column boundaries which function as channels for Sr to diffuse to the GDC-ScYSZ interface. By tuning deposition temperature, bias voltage and film thickness area specific resistances down to 0.34 Ω cm2 are achieved at cell tests performed at an operating temperature of 650 °C. © 2014 Elsevier B.V. All rights reserved.
Journal of Power Sources, 2014, Vol 267, p. 452-458
CGO; GDC; Physical vapor deposition (PVD); Solid oxide fuel cell (SOFC); Adatoms; Bias voltage; Cathodes; Deposition; Diffusion coatings; Electrolytes; Film thickness; Magnetrons; Physical vapor deposition; Solid oxide fuel cells (SOFC); Temperature; Area-specific resistances; Deposition temperatures; Electrochemical performance; Metal-supported solid oxide fuel cells; Reactive magnetron sputtering; Substrate bias voltages; Scandium
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