PVD-Technologie · 2018. 6. 26. · PVD-Technologie Thomas Götsch Institut für Physikalische...

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



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


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


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


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


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



4. Conclusion

1. Introduction

1. Introduction


4. Conclusion


Characterization of the Model Anodes 11

T. Götsch14.11.2016


Composition – Depth Profiles


T. Götsch14.11.2016


Chemical State Depth Profiling: YSZ

• Surface: fully oxidized

• Etching: Zr is reduced (preferential O-sputtering)

• Close to substrate: reduction


T. Götsch14.11.2016


Chemical State Depth Profiling: Nickel/copper


T. Götsch14.11.2016


YSZ: Morphology

• polycrystalline cubic YSZ

• about 10 nm grain size


T. Götsch14.11.2016


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


4. Conclusion


Tolerance towards SOFC Fuels 18

T. Götsch14.11.2016


Carbon Deposition: CH4 at 800 °C

NiCu/YSZ

NiCu


T. Götsch14.11.2016


Crystallography

θ

YSZ

YSZ Methane

NiCu

NiCu Methane

NiCu/YSZ

NiCu/YSZ Methane


T. Götsch14.11.2016


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)


T. Götsch14.11.2016


Surface Topology

1. Introduction


4. Conclusion


1. Introduction



4. Conclusion

Conclusion 24

T. Götsch14.11.2016


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


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/

PVD-Technologie · 2018. 6. 26. · PVD-Technologie Thomas Götsch Institut für Physikalische...

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