Proton Conducting Electrolysers with Tubular Segmented-in-series - - PowerPoint PPT Presentation

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Proton Conducting Electrolysers with Tubular Segmented-in-series - - PowerPoint PPT Presentation

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Proton Conducting Electrolysers with Tubular Segmented-in-series Cells for Hydrogen Production Marie-Laure Fontaine 1 , Einar Vllestad 2 , Jonathan M. Polfus 1 , Wen Xing 1 , Zuoan Li 1 , Ragnar Strandbakke 2 , Christelle Denonville 1 , Truls

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SLIDE 1

Proton Conducting Electrolysers with Tubular Segmented-in-series Cells for Hydrogen Production

Marie-Laure Fontaine1, Einar Vøllestad2, Jonathan M. Polfus1, Wen Xing1, Zuoan Li1, Ragnar Strandbakke2, Christelle Denonville1, Truls Norby2, Rune Bredesen1

1 SINTEF Materials and Chemistry, Norway 2 University of Oslo, Norway

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SLIDE 2

2

PCE SOE

2H2O

ΔH 2H2 + O2

Ceramic Electrolysers: utilizing waste heat

Solid Oxide Electrolyzers (SOE)

  • Well proven technology
  • Long term stability challenges
  • Delamination of O2-electrode
  • Higher temperature

Proton Ceramic Electrolysers (PCE)

  • Less mature technology
  • Fabrication and processing challenges
  • Produces dry H2 directly
  • Potentially intermediate temperatures
  • Slow O2-electrode kinetics
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SLIDE 3

Operating Principles of Proton Ceramic Electrolysers (PCEs)

3

Anode Cathode Electrolyte

2H2O O2 4H+

U e- 2H2O  O2 + 4H+ +4e- 0  e- + h+

h+

e- + h+  0 Rion Zel,a Zel,c Re-

4H+ +4e-  2H2

O2-

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SLIDE 4

4

Development of tubular cathode supported electrolyte cell Development and

  • ptimization of anodes

and current collection Single tube module development and testing Multi-tube module testing Aim: 1kW demo

H+ H+ H+ O2 H2O e- e-

BZY

O2 e- O2 H+ H+ H+ H2O e- e-

BZY

O2 e- H+ H+ H+ O2 H2O e- e-

BZY

O2 e- O2-

Protonic conductor e- Conductor nanoparticles Mixed Oxygen ion-electronic conductor

a b c

Process integration and evaluation

High temperature electrolyser with novel proton ceramic tubular modules (2014-2017)

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SLIDE 5

Scaling up tubular proton ceramic electrolysers

  • Why tubular design?
  • Simpler sealing technology, lower sealing area
  • Better stress distribution during transient

conditions

  • Module design enables to close off a tube /

replace it

  • Segmented-in-series cells
  • Retain high voltage
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SLIDE 6

6

Dip-coating suspensions BZCY-NiO paste

Wet milling of precursors Solid State Reactive Sintering Extrusion of BZCY-NiO support Spray- or dip-coating

Scaling up tubular proton ceramic electrolysers

BaZr0.7Ce0.2Y0.1O3-δ (BZCY72)

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SLIDE 7

7

Dense electrolyte @ 1550°C – 24h 1610°C – 6h

Scaling up tubular proton ceramic electrolysers

40 μm

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SLIDE 8

8

Development of new steam electrode materials

1.0 1.1 1.2 1.3 1.4 1.5 1.6

  • 1.5
  • 1.0
  • 0.5

0.0 0.5 1.0 1.5

GBCF / BZCY BSCF / BCY Pr2NiO4 / BCY LSCF / BCY BGCF / BCY BGLC (x=0) / BZCY BCZF

log ((Rp (Ωcm

2)

1000/T (K

  • 1)

750 700 650 600 550 500 450 400 350

T (°C)

Ba1-xGd0.8La0.2+xCo2O6-δ displays best PCE steam electrode performance (symmetrical disk samples)

0.8 1.0 1.2 1.4 1.6 1.8

  • 2
  • 1

1 2

X = 0.1 X = 0.5 X = 0* X = 0.3 Log(Rp,app(Ωcm

2))

1000 / T (K

  • 1)

800 600 400 0.01 0.1 1 10 100

Rp,app(Ωcm

2)

T (°C) 0.04 Ωcm

2

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SLIDE 9

9

Steam electrode processing

1. Cap and seal using glass-ceramic from CoorsTek 2. Deposit Ba0.7Gd0.8La0.5Co2O6-δ as steam electrode by paint brush 3. Firing in dual atmosphere:

  • 1000 °C
  • 2% O2 outside, 5% H2 inside
  • Ecell = 1.4 V during firing

4. Gold paste applied as current collector

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SLIDE 10

10

Electrolysis with BGLC electrode

1 2 3 4 5 550°C 600°C 650°C 700°C

Current (A)

700°C 650°C 600°C 550°C

H2 production (NmL min

  • 1)

F a r a d a i c H

2

p r

  • d

u c t i

  • n

0.00 0.25 0.50 0.75 1.00 50 100 150 200 1.0 1.5 2.0

700°C 600°C 550°C 650°C

Potential (V) Current density (mA cm

  • 2)

Anode: pO2 = 30 mbar pH2 = 0.3 bar ptot = 3 bar ptot = 3 bar pO2 = 80 mbar pH2O = 1.5 bar Cathode:

1.0 1.5 2.0 40 60 80 100 550°C 600°C 650°C 700°C

Faradaic efficiency (%) Potential (V)

4 5 6 7 8 3 2 1

  • 1

OCV 50 100 300

Z

// (Ωcm 2)

Z

/ (Ωcm 2)

bends off Post-characterization: poor electrode adhesion

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SLIDE 11

11

Steam electrode processing

1. BZCY72-Ba0.5Gd0.8La0.7Co2O6-δ applied as steam electrode

  • Fired in air at 1200°C for 5h
  • Infiltrated with nanocrystalline

Ba0.5Gd0.8La0.7Co2O6-δ

  • Thin Pt layer current collection

2. Capped and sealed at 1000°C

  • Semi-dual atmosphere to keep BGLC

layer intact

3. NiO reduction at 800°C in 10% H2 for 24h

  • Kept in electrolytic bias during

reduction to avoid re-oxidation

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SLIDE 12

12

Electrolysis with BZCY-BGLC composite electrode

5 10 15 20 400°C 500°C 600°C

H2 production (NmL min

  • 1)

Faradaic H2 production 700°C 100 200

Current Density (mA cm

  • 2)

1 2 3 1.0 1.5 2.0 Anode: pO2 = 30 mbar pH2 = 0.5 bar ptot = 3 bar ptot = 3 bar pO2 = 30 mbar 400°C 500°C 600°C

Voltage (V) Current (A)

700°C pH2O = 1.5 bar Cathode:

4 5 6 7 8 9

  • 2

2 4 Zreal (Ωcm

2)

400°C 500°C 600°C

  • Zim

700°C 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Zreal (Ω)

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SLIDE 13

Improved faradaic efficiency primarily due to enhanced electrode kinetics

13

4 5 6 7 8 9

  • 2

2 4 Cell 1

Z

// (Ωcm 2)

Z

/ (Ωcm 2)

Cell 2 600C 30 mA cm

  • 2

50 100 150 200 1.0 1.5 2.0

Cell 1 Cell 2 Voltage (V) Current density (mA cm

  • 2)

20 40 60 80 100

Faradaic efficiency (%)

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SLIDE 14

Porous support H2 electrode H2O+O2 electrode Novel interconnects Electrolyte

14

Segment-in-series: print masking

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SLIDE 15

15

Segment-in-series: print masking

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SLIDE 16

Segment-in-series: print masking

16

Temperature:

  • 1500 °C
  • 1525 °C
  • 1530 °C
  • 1540 °C
  • 1550 °C
  • 1600 °C
  • Addition of pore formers

(A) in the electrode + reduction of temperature

Support

Various thermal profiles Dwell:

  • 2h
  • 5h
  • 10h

Pore formers and sintering aid

  • Addition of sintering aid

+ pore formers (B) in the support

RT RT 100°C 350°C xx°C – xxh 1450°C – xxh

1.6°C/min 1.6°C/min 0.5°C/min 0.5°C/min

RT RT xx°C – 10h

1.6°C/min 1.6°C/min

Electrolyte Electrode

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SLIDE 17

NiO- BZCY BZCY NiO- BZCY BZCY NiO- BZCY Support Support

Collar for hang-firing

Segment-in-series: print masking

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SLIDE 18

18

30 µm 300 µm

NiO-BZCY72 BZCY72 BZCY72

BZCY72 NiO-BZCY72 BZCY72 30 µm 30 µm

Segment-in-series: print masking

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SLIDE 19

Conclusions

  • Tubular PCEs fabricated
  • BZCY-NiO tubular cathode support
  • Spray coated BZCY72 electrolyte
  • BGLC-BZCY72 steam electrode
  • Enhanced faradaic efficiencies observed with improved anode performance
  • Current densities of 220 mA cm-2 at 600°C obtained with > 80% faradaic efficiency
  • PCEs may suffer from electronic leakage due to p-type conductivity in oxidizing conditions

50 100 150 200 1.0 1.5 2.0

Cell 1 Cell 2 Voltage (V) Current density (mA cm

  • 2)

20 40 60 80 100

Faradaic efficiency (%)

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SLIDE 20

Acknowledgements

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement n° 621244.

Marie-Laure Fontaine1, Einar Vøllestad2, Jonathan M. Polfus1, Wen Xing1, Zuoan Li1, Ragnar Strandbakke2, Christelle Denonville1, Truls Norby2, Rune Bredesen1

1 SINTEF Materials and Chemistry, Norway 2 University of Oslo, Norway