Post on 26-Mar-2021
PVD-Technologie
Thomas GötschInstitut für Physikalische Chemie
Universität Innsbruck
Modell-Mikro-Festoxid-Brennstoffzellen
Energieforschung (e!MISSION) Projekt-Nr. 848825
Leitung: PD Dr. Simon Penner
Partnerinstitution: Joanneum Research
1. Introduction
2. Characterization of the Anodes
3. Tolerance towards SOFC Fuels
4. Conclusion
2. Characterization of the Anodes
3. Tolerance towards SOFC Fuels
4. Conclusion
1. Introduction
Introduction 4
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Solid Oxide Fuel Cells
fuel
electrons
air
O2
H2O, CO2
O2-H2
CH4
electrolyteanode cathode
Ni/YSZperovskites
solid oxide: YSZ doped CeO2 perovskites
perovskitesplatinum
H2, hydrocarbons (CH4, …)
Introduction 5
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
SOFC Anodes
Atkinson et al. Nature 2004, 3, 17–28
Toebes et al. Catal. Today 2002, 76, 33–42
• Ni/YSZ: not stable in C-rich fuels
• alloying of Ni with Cu: reduction of C-deposition
• porous: transport of fuel to three-phase boundary
• if fuel is not hydrogen
• either catalytic conversion to H2 (steam reforming)
• or direct oxidation of the fuel
Introduction 6
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
SOFC Anodes
Atkinson et al. Nature 2004, 3, 17–28
Toebes et al. Catal. Today 2002, 76, 33–42
Kim et al. J. Electrochem. Soc. 2002, 149, A247–A250
• Ni/YSZ: not stable in C-rich fuels
• alloying of Ni with Cu: reduction of C-deposition
Cu/Ni: (a) > (b) > (c) > (d) > (e)
Introduction 7
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Advantages of Micro-SOFCs
• thinner electrolyte: lower operating temperature?
• lower thermal mass
• less energy required
• increased lifetime
• lower running costs
conventional SOFC
anode-supported SOFC
Micro-SOFC?
800
– 10
00 °
C
600
– 70
0 °C
<
600
°C
Introduction 8
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
PREPARATION OF THE MODEL ELECTRODES
substrate
NSN
target
• Physical vapour deposition methods: thinner films than conventional techniques
• high vacuum: high purity
• magnetron sputtering: high deposition speed
• plasma at target sputters off the material
Samples:• 8YSZ
• NiCu
• NiCu/8YSZ
on Si, NaCl
2. Characterization of the Anodes
3. Tolerance towards SOFC Fuels
4. Conclusion
1. Introduction
1. Introduction
3. Tolerance towards SOFC Fuels
4. Conclusion
2. Characterization of the Anodes
Characterization of the Model Anodes 11
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Composition – Depth Profiles
Characterization of the Model Anodes 12
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Chemical State Depth Profiling: YSZ
• Surface: fully oxidized
• Etching: Zr is reduced (preferential O-sputtering)
• Close to substrate: reduction
Characterization of the Model Anodes 13
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Chemical State Depth Profiling: Nickel/copper
Characterization of the Model Anodes 14
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
YSZ: Morphology
• polycrystalline cubic YSZ
• about 10 nm grain size
Characterization of the Model Anodes 15
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
YSZ Phase Transition
Red data points from Götsch et al. AIP Adv. 2016, 6, 025119
• unit cell height (from diffraction)
• tetragonal/cubic phase transformation between 8 and 9.3 mol% Y2O3
1. Introduction
3. Tolerance towards SOFC Fuels
4. Conclusion
2. Characterization of the Anodes
1. Introduction
2. Characterization of the Anodes
4. Conclusion
3. Tolerance towards SOFC Fuels
Tolerance towards SOFC Fuels 18
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Carbon Deposition: CH4 at 800 °C
NiCu/YSZ
NiCu
Tolerance towards SOFC Fuels 19
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Crystallography
θ
YSZ
YSZ Methane
NiCu
NiCu Methane
NiCu/YSZ
NiCu/YSZ Methane
Tolerance towards SOFC Fuels 20
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Spectrum Imaging: Elemental Distribution
Scale bars: 200 nm
Scale bars: 2 µm
• mixed Ni-Cu particles with varying composition
• partially oxidized (esp. Ni-rich crystallites)
• Core-shell particles Ni-rich core, Cu-rich shell
• C-deposition for faces with Ni/Cu = 3.5 to 5
• no carbon for Ni/Cu = 0.5 (blue arrows)
Tolerance towards SOFC Fuels 21
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Surface Topology
1. Introduction
2. Characterization of the Anodes
4. Conclusion
3. Tolerance towards SOFC Fuels
1. Introduction
2. Characterization of the Anodes
3. Tolerance towards SOFC Fuels
4. Conclusion
Conclusion 24
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
Summary & Outlook• NiCu treated in methane shows core-shell structure
• Cu-rich surfaces inhibit carbon deposition
• can be achieved by prereduction of NiCu[1]
• tetragonal/cubic YSZ phase transition could be narrowed down to lie between 8 and 9.3 mol% Y2O3
• preparation of Micro-SOFC is feasible
• addition of a cathode to the NiCu/YSZ model anode
• reduction of operating temperature, running costs and increase of life time of SOFCs
[1] Kim et al. J. Electrochem. Soc. 2002, 149, A247–A250
Conclusion 25
T. Götsch14.11.2016
Physikalische Chemie, Universität Innsbruck PVD-Technologie — Modell-Mikro-Festoxid-Brennstoffzellen
AcknowledgementsProjektleitung:
• PD Dr. Simon Penner Nanostructured Model Catalysts Innsbruck Institut für Physikalische Chemie Universität Innsbruck
Experimente:
• Thomas Götsch, MSc Nanostructured Model Catalysts Innsbruck Institut für Physikalische Chemie Universität Innsbruck
Probenpräparation
• Dr. Reinhard Kaindl Institut für Oberfächentechnologien und Photonik Joanneum Research — Materials
http://webapp.uibk.ac.at/physchem/nmci/