Development of proton conducting electrolyser cells Marie-Laure Fontaine, Christelle Denonville, Jonathan Polfus, Wen Xing, Paul Inge Dahl, Tor Olav Sunde, Rune Bredesen SINTEF Materials and Chemistry Thin Film and Membrane Technologies Department SINTEF Materials and Chemistry 1
High temperature electrolysers with novel proton ceramic tubular modules (2014-2017) Fabrication of BZY-based segmented-in-series tubular electrolyser cells Multi-tubes module development H 2 production from DME/Ethanol production from steam and electricity steam, CO 2 and electricity 20 µm 50 µm U 2H 2 O 3/2O 2 4e - 2H 2 O 4H + 4H + O 2- 2H 2 Development of mixed O 2 proton-electron CO+2H 2 CO 2 conducting anodes 100 µm a b O 2 c O 2 O 2 O 2 O 2 H 2 O H 2 O H 2 O e - e - e - e - e - e - H + H + H + e - e - e - O 2 O 2- H + H + H + BZY H + BZY H + BZY H + e - Conductor Protonic conductor Mixed Oxygen ion-electronic conductor nanoparticles SINTEF Materials and Chemistry
Solid State Reactive Sintering (SSRS) Wet milling of precursor powders: NiO + BaCO 3 , Y 2 O 3 , ZrO 2 , CeO 2 Limited number of processing steps Fine Homogeneous microstructure Drying of powders in oven Fast sintering Pressing and sintering at T > 1400 ° C BZCY based dense pellets with 1 wt. % NiO • Cost effective • Lower CO 2 emissions G. Coors 2011, www.intechopen.com J. Tong, Ryan O'Hayre et a., J. Mater. Chem., 2010, 20 SINTEF Materials and Chemistry 3
SSRS for enabling cells production in ELECTRA BZY10: BaZr 0.90 Y 0.10 O 3- δ BZY10 or BZCY72 BZCY72: BaZr 0.70 Ce 0.20 Y 0.10 O 3- δ Fuel electrode: NiO + BaCO 3 ,Y 2 O 3 , ZrO 2 Electrolyte: BaCO 3 ,Y 2 O 3 , ZrO 2 NiO+ BZY10 or NiO + BZCY72 (60/40 vol. %) and Fuel electrode: NiO + BaSO 4 ,Y 2 O 3 , ZrO 2 , Notation: BZY10 // BZY10-NiO with and without CeO 2 Electrolyte Electrode Electrolyte: BaSO 4 ,Y 2 O 3 , ZrO 2 , with and without CeO 2 SINTEF Materials and Chemistry 4
Solid state reactive sintering for BZY based cell production SONATE 100 m 2 clean room Pastes and Electrolyte Extrusion of Co-sintering suspensions deposition fuel electrode Drying in air Drying in air Wet milling of SSRS based precursors 10-25 cm long tubes Automatic dip-coater Max 1m long tube Dip-coating suspensions NiO based paste 40-ton extruder with automatic capping, cutting and air transport belt SINTEF Materials and Chemistry 5
Investigated parameters • Fuel electrode • Dip- extrusion coating of electrolyte • Paste formulation • Suspension (solid loading, binder formulation (solid and water content) loading, binder • Mixing procedure content) • Extrusion parameters • Milling procedure • Drying and polishing • Coating parameters • Temperature, dwell time • Temperature • Heating & cooling rates • Atmosphere • Atmospheres • Reduction • Co- of half-cells sintering SINTEF Materials and Chemistry 6
Drying and polishing "Green" tubes after coating Close end Dried tubes after from capping polishing with system wet clean room tissue 15 cm Tubes after extrusion and roll- drying in air for 24h SINTEF Materials and Chemistry 7
SSRS-based suspensions "Foam" • Water-based suspension ( cellulose based binder ) BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 Anti-foaming • Organic-based suspension Viscosity 110-175 cP at 60 rpm with LV2 spindle BaCO 3 , Y 2 O 3 , ZrO 2 , CeO 2 Protocol: Planetary milling of powders + binders + water or solvent @ 300 rpm – 2h Viscosity around 19 cP at 60 rpm using LV2 spindle SINTEF Materials and Chemistry 8
BZY10 // BZY10-NiO using BaCO 3 based precursor mixture 1610 ° C - 6h: surface view of electrolyte 1610 ° C - 6h: surface view of uncoated electrode BaNiY 2 O 5 100 microns NiO 40 microns 10 microns BaNiO 2 SINTEF Materials and Chemistry 9
BZY10 // BZY10-NiO using BaCO 3 based precursor mixture 1550 ° C - 24h BaNiY 2 O 5 BaNiO 2 100 microns 10 microns 40 microns 10 microns SINTEF Materials and Chemistry 10
BZY10 // BZY10-NiO using BaCO 3 based precursor mixture Wet 4%H 2 /Ar @ 900 ° C Y 2 O 3 BaNiY 2 O 5 Ni 4 microns 40 microns BaNiY 2 O 5 Cracks in electrolyte SINTEF Materials and Chemistry 11
SSRS BZY pellet with 2wt% NiO HT-ESEM Dilatometry in air HT XRD BaNiY 2 O 5 5 0 Thermal expansion (%) -5 50 μ m 50 μ m 897°C 1067°C -10 -15 -20 0 200 400 600 800 1000 1200 1400 Temperature (°C) 50 μ m 50 μ m J. Tong, Ryan O'Hayre et a., J. Mater. Chem., 2010, 20 1238°C 1288°C SINTEF Materials and Chemistry 12
SSRS BZY pellet with 2wt% NiO 4 microns 2 θ 40 30 50 60 BaNiY 2 O 5 1 microns SINTEF Materials and Chemistry 13
Investigated half-cells with BaSO 4 precursor BZCY72 BZY10 BZY10 BZCY72 - NiO BZY10 - NiO BZCY72 - NiO SINTEF Materials and Chemistry 14
100 microns 100 microns 100 microns BZY10 // BZCY72-NiO BZCY72 // BZCY72-NiO BZY10 // BZY10-NiO Dense electrolyte @ Porous electrolyte @ Dense electrolyte @ 1550 ° C – 24h 1550 ° C – 24h 1550 ° C – 24 h 1610 ° C – 6h 1610 ° C – 6h 1610 ° C – 6 h 1650 ° C – 6h 40 microns 40 microns 1670 ° C – 6h 40 microns SINTEF Materials and Chemistry 15
Grain size: BZCY72 // BZCY72-NiO 5-10 microns 1610 ° C – 6h 1550 ° C – 24h Grain size: Large: 5 microns Small: 2 microns Grain growth 10 microns 10 microns 10 microns 100 microns 10 microns SINTEF Materials and Chemistry 16
Reduction of half-cells Wet Harmix at 900 ° C • Hg-porosimetry 0,25 1550 °C, 24h Incremental Intrusion, mL·g -1 0,20 1610 °C, 6h 0,15 0,10 0,05 0,00 100 1000 10000 Diameter, nm 40 microns Between 27-32 vol% porosity (with 60 vol% Ni) SINTEF Materials and Chemistry 17
BZY10 // BZY10-NiO 1670 ° C – 6h 1610 ° C - 6h 100 microns 100 microns 10 microns NiO 10 microns 4 microns 10 microns BaNiY 2 O 5 SINTEF Materials and Chemistry 18
BZY10 "BZY10"//BZCY72-NiO BZCY72 - NiO 2 % Ce in BZY 100 microns 10 microns SINTEF Materials and Chemistry 19
Characterization HT-XRD up to 1200 ° C • BaSO 4 Phases evolution • BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 or without CeO 2 TGA / DSC up to 1400 ° C • NiO - BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 or without CeO 2 HT-ESEM up to 1400 ° C • Green half-cells Microstructural • Green coated half-cells Ex-situ SEM-EDS analyses evolution Half-cells annealed from 1550 ° C – 1670 ° C • • BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 or without CeO 2 Dilatometry (push rod) up to • NiO - BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 or without CeO 2 1500 ° C Sintering behaviour Fast sintering up to 1600 ° C • Green half-cells SINTEF Materials and Chemistry 20
TGA/DSC in air BaSO 4 Ortho to & HT-XRD cubic XRD: BaSO 4 Pbnm Shift in relative peak intensity Optical dilatometry Relative shrinkage % Temperature C SINTEF Materials and Chemistry 21
NiO - BaSO 4 , Y 2 O 3 , ZrO 2 , CeO 2 SSRS mixture BZY10-NiO SSRS mixture BZCY72-NiO BaSO 4 powder SINTEF Materials and Chemistry
Heating to 1600 ° C @ 2 ° C/min - 10 min dwell 100 microns 100 microns BZCY72 // BZCY72-NiO BZY10 // BZY10-NiO NiO ensures mechanical strength BZCY72+NiO ensure mechanical strength SINTEF Materials and Chemistry 23
Summary Cross-section view of air electrode • Sintering of BZY10 electrolyte not yet achieved • Further experiments in progress to understand limiting factors • Successful fabrication of tubular half-cells with BCZY based electrolytes (20%Ce; 2%Ce) • Samples are given for air electrode development Presentation Einar Vøllestad A8.03 SINTEF Materials and Chemistry 24
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. Research Council of Norway for the BIOPCFC project (number 219731/O70) My colleagues at ELECTRA: Dr. Dustin Beeaff (CoorsTek Membrane Sciences) Prof. Truls Norby (UiO) Ragnar Strandbakke (UiO) Dr. Anna Magraso (UiO, CSIC) SINTEF Materials and Chemistry 25
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