Nickel-free Hybrid Metal-Ceramic Supported SOFC R. Costa [email protected]
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 1
Alantum Europe GmbH: R. Poss, ARMINES: A. Chesnaud, F Willot CerPoTech: G. Syvertsen, CNR: M. Viviani, A. Sanson
Grenoble INP: L. Dessemond Ceraco GmbH: R. Semerad Saan Energi: A. Ansar
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 2
Aeronautics Space Transport Energy Space Agency Project Management Agency
Research Institution
DLR German Aerospace Center
Cologne
Oberpfaffenhofen
Braunschweig
Goettingen
Berlin
Bonn
Neustrelitz
Weilheim
Bremen Trauen
Lampoldshausen
Stuttgart
Stade
Augsburg
Hamburg
Juelich > 7500 employees across 32 institutes and facilities at 16+1 sites.
Offices in Brussels, Paris, Washington.
Generations of planar SOFCs > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 3
1st gen.
2nd gen.
3rd gen.
ESC
Limited power density Fuel flexibility Robustness
Stationary Transportation
High power density Fuel flexibility
Sulfur poisoning Thermal cycling Redox Cycling
Stationary Transportation
High power density Fuel flexibility
Sulfur poisoning Thermal cycling Redox Cycling
Stationary Transportation
ASC
MSC
Electrolyte
Cathode
Anode
30 µm
25 µm
35 µm Bipolar plate
Bipolar plate
porous metallic substrateanodeelectrolyte
contact layercathode current collectorcathode active layer
protective coating
not used airoxygen/air
air channel
fuel channel
fuel brazing not used fuel + H O2
(not in scale)
Plasma Deposition Technology
Ferritic Substrates and Interconnects
Compact Design with Thin Metal Sheet Substrates
Brazing, Welding and Glass Seal as Joining and Sealing Technology
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 4
3rd Gen. SOFC: MSCs at DLR
Vortrag > Autor > Dokumentname > Datum
MSC Cell 12.5 cm² cell at 800°C; H2/N2 and air
10 Cells Stack 100 cm² single cells at 800°C; H2/N2; air
MSC-10-31, 800°C, 27h10H2+10N2/ 20 Luft (SLPM)
P1: Kennlinie nach Aufheizen, KL1
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
1,1
1,2
0 100 200 300 400 500Stromdichte i [mA/cm²]
Zells
pann
ung
U [V
]
0
200
400
600
800
Leis
tung
sdic
hte
p [m
W/c
m²]
OCVZelle 10: 1,019 VZelle 9: 1,006 VZelle 8: 1,007 VZelle 7: 1,001 VZelle 6: 1,006 VZelle 5: 1,016 VZelle 4: 1,022 VZelle 3: 1,005VZelle 2: 1,013VZelle 1: 1,014 V
@ 7,0 VPstack = 250 WFU = 24,8 mol%
p
U
Stromdichte@ 700mVZelle 10: 173 mW/cm²Zelle 9: 315Zelle 8: 324Zelle 7: 325 mW/cm²Zelle 6: 318Zelle 5: 324 mW/cm²Zelle 4: 329Zelle 3: 320 mW/cm²Zelle 2: 319Zelle 1: 320 mW/cm²
3rd Gen. SOFC: MSCs at DLR > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 5
0,6
0,7
0,8
0,9
1
1,1
0 400 800 1200 1600
Current density / mA*cm-2
Cel
l vol
tage
/
V
0
250
500
750
1000Po
wer
den
sity
/
m
W*c
m-2
A BC D
APS
SPPS
• P. Szabo, J. Arnold, T. Franco, M. Gindrat, A. Refke, A. Zagst, A. Ansar, ECS Transactions, 2009 (25) 2 p.175-185
• D. Soysal, A. Ansar, Z. Ilhan, R. Costa, ECS transactions, 2011 (35) 1 p.2233-2241
Issues to be adressed for improving MSCs
• Cr-poisoning at the cathode side > Protective coating required • Improve tolerance toward sulfur poisoning
• Life time of metal substrate if stationary applications are considered
• Hermitic electrolyte
Beyond the 3rd Gen. SOFC:
Which materials and architecture for the next generation of SO(F)C?
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 6
Metallic alloy foam (such as FeCrAlY), capable of forming alumina protective scale Excellent mechanical properties, but high sensitivity to chemical reactions (high degradation)
Oxidized metal alloy foam, with stable aluminum oxide scale Excellent mechanical properties and stable oxide scale to protect against chemical reactions (low degradation), but poor or no electronic conductivity
Anodization
Metal substrate resistant toward oxidation
Al rich alloys, on the basis of MCrAl(Y) with M being Fe, Ni, Co or a mixture
Formation of an Al2O3 layer as a durable protective coating
Nickel-free Hybrid Metal-Ceramic Supported SOFC
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 7
Impregnation
Anode current collector - Oxidized alloy foam with impregnated conductive ceramic (LSCM or LST). Excellent mechanical properties and stable oxide scale to protect against chemical reactions (low degradation), high electronic (and ionic) conductivity
Roughness Adjustment
Smooth current collector Low roughness surface ready for coating of functional layers of cell
Hybrid current collector mechanically and chemically stable in both oxidant and reducing atmosphere
Infiltration with an electronic conductor (ideally a ceramic)
Target : 100 S/cm
Dense La0.1Sr0.9TiO3 (800°C): - sintering in H2: σtot ≈ 150 S/cm O. Marina et al. Solid State Ionics, 149 (2002) 21-28. S. Hashimoto et al. Journal of Alloys and Compounds, 397 (2005) 245-249. Y. Tsvetkova et al. Materials and Design, 30 (2009) 206-209.
Nickel-free Hybrid Metal-Ceramic Supported SOFC
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 8
Fabrication of functional layers on top of anode current collector+ infiltration
Realization of Evolve Cell LSCF-CGO cathode CGO diffusion barrier layer YSZ or ScSZ Electrolyte LSCM-CGO anode (with infiltrated Ni)
Use of perovskite materials at the anode
and cathode, being modified by addition of
suitable catalysts
High power density, Sulfur resistant, Fuel flexibility, Thermal cycling, Redox Cycling
Stationary applications …
Nickel-free Hybrid Metal-Ceramic Supported SOFC
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 9
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 10
Composition of the anode: Ce1-xGdxO2-α / La0,1Sr0,9TiO3-α Electrolyte: 8-YSZ Cathode : Ce1-xGdxO2-α / La0,4Sr0,6Co0,2Fe0,8O3-α
Nickel-free Hybrid Metal-Ceramic Supported SOFC
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 11
Development strategy
1cm² 15-20 cm² 100 cm²
- Reactivity tests - Conductivity measurement - Understanding the behaviour
- Shaping strategy - Prototype - Testing and optimization
- upscaling
(CNR ISTEC)
(DLR)
10mm
10mm
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 12
Evaluation of the anodic electrocatalyst
• Symetrical cells tested in 3-electrodes configuration
• Experimental conditions Gas composition, gas flow, Temperature • Elaboration parameters Composition, Thickness porosity
RE
WE
CE
Φ = 16 mm
≈ 2 mm
anode
YSZ
Au grids Au wire
Au wire
Au wire
alumina
P
Evaluation of the electrocatalyst > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 13
Rpol decreases: increase in thickness and/or decrease of the pore size
Electrokinetic modeling • Reaction mechanism and kinetic data • Thermodynamic data
⇒ detailed multistep (electro-)chemical mechanism
⇒ thermodynamically consistent kinetic modeling
⇒ evaluation of main performance limitation processes
R1:
R2:
R3:
R4:
C1:
C2:
Evaluation of the electrocatalyst > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 14
97 % H2, 3% H2O, OCV LST-CGO20, 50 vol%-50 vol % screen printing Data - Anode: 15 μm - Electrolyte: 925 μm - Mesh: 700 μm - Inlet: 50 mL/min/cm2
- Active surface area: 4.6 104 m2/m3
⇒ - qualitative agreement between modeling and experiments
- three main impedance features
Electrochemical results: IST20
Evaluation of the electrocatalyst > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 15
interfacial charge transfer
⇒ - unambiguous assignment of impedance features
- influence of surface chemistry
Efficient LST based anodes requires high specific surface area
surface charge transfer
97 % H2, 3 % H2O, OCV
Evaluation of the electrocatalyst > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 16
Solid line: full model Dashed line: reduced to 1D ⇒ ideal supply channel transport Dashed-dotted line: reduced to 1D with CDL = 0
H2O dissociation
gas conversion impedance
⇒ - separation of transport and chemistry
- cell design optimization
Evaluation of the electrocatalyst > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 17
V. Yurkiv, G. Constantin, A. Hornes, A. Gondolini, E. Mercadelli, A. Sanson, L. Dessemond, R. Costa, submitted to Journal of Power Sources
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 18
Evaluation of the current collector
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 19
0
2 0 0
4 0 0
6 0 0
8 0 0
0 . 0 1
0 . 1
1
0 1 0 0 2 0 0 3 0 0
H 2
Tem
pera
ture
(°C
)
Time (hour)
Tota
l con
duct
ivity
(S/c
m)
Evaluation of the current collector
Reduction at 750 °C under H2
Total conductivity << 100 S/cm
LST-NiCrAl current collector > Cathode sintering leads to full reoxidation of LST Evaluation of in-situ reduction of LST during stack sealing/commissioning
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 20
0
2 0 0
4 0 0
6 0 0
8 0 0
1 0 0 0
0 2 0 4 0 6 0
H 2 H 2 A i r A i r H 2
Tem
pera
ture
(°C
)
Tota
l con
duct
ivity
(S/c
m)
1
10
0.1
0.01
0.001
Evaluation of the current collector
Total conductivity << 100 S/cm
Reduction at 900 °C under H2
LST-NiCrAl current collector > Cathode sintering leads to full reoxidation of LST Evaluation of in-situ reduction of LST during stack sealing/commissioning
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 21
Full Cell Processing
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 22
First demo Prototype through Plasma Spraying Route
100µm thick electrolyte
Cathode
Co-pressed LST-CGO infiltrated NiCrAl foam
OCV for 140h
At 180mA for 180h
Low risk approach using the know how from DLR for spraying YSZ layers. No need of sintering step.
0
0.2
0.4
0.6
0.8
1.0
1.2
0 10 20 30 40 50 0
5
10
15
i / 10-3 A.cm-2
pote
ntai
l / V
pow
er d
ensi
ty /
mW
.cm
-2
H2/N2, 62 mL/min/cm2
Cell S1, 769°C
0
0.2
0.4
0.6
0.8
1.0
1.2
0 10 20 30 40 0
5
10
15
20
i / 10-3 A.cm-2
pote
ntai
l / V
pow
er d
ensi
ty /
mW
.cm
-2
H2/N2, 62 mL/min/cm2
Cell S2, 764°C
⇒ - stable OCV and polarization
curves for 50 hours
- 10-15 mW.cm-2 at 0.7 V in H2-air
- leakage (OCVexp < OCVNernst)
4 3 2 1 0
-1 -2
5 6 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
H2, 62 mL/min/cm2
Re(Z) / Ω.cm2 - Im
(Z) /
Ω.c
m2
Cell S1, OCV = 0.98 V before, 769°C after, 794°C
2 1 0
-2 -1
3 2 1
0 -1 -2 4
8
3 2
7
4
Prototype > ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 23
towards thin films electrolyte
Current collector
Active Anode
Nanostructured YSZ Buffer layer
CGO Layer
3µm
Active anode
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 DLR.de • Chart 24
2
1
0
-1
H2/N2, 62 mL/min/cm2
12 13 14 15 16 17 18 Re(Z) / Ω.cm2 - I
m(Z
) / Ω
.cm
2
Cell P1, 793°C, OCV = 0.4 V
4 3
2 1 0
-2 -1
Cell P: - low OCV
- no polarization curves
- high Rs but low Rpol
4
2
0
-2
H2/N2, 62 mL/min/cm2 before, 764°C after, 771°C
Cell S2, OCV = 1.03 V
- Im
(Z) /
Ω.c
m2 3
4
2 1
0 -1 -2 3 1 0
-2 4
2
-1
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Re(Z) / Ω.cm2
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015
towards thin film electrolytes 25
• La0,1Sr0,9TiO3-α Requires high specific surface area
Requires specific treatment for full activation
• Reducibility and maximum level of perovskites electrocatalysts needs to be enhanced
• Implementation of metals seems necessary to achieve conductivity target in the current collector
> demonstration up to 100cm² cell of SOC
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 26
Conclusion & perspectives
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 27
Acknowledgement FCH JU for funding under the grant Agreement n°303429
F. Han (for coatings), V. Yurkiv (modelling), G. Schiller, Prof. K.A. Friedrich,
Thank you for your attention!
> ICACC15 > R.Costa • Ni-free Hybrid Metal-Ceramic Supported SOFC > 29. January 2015 28
Top Related