Development of Tubular Proton Ceramic Electrolysers (PCEs) Vigen 4 , - PowerPoint PPT Presentation

Development of Tubular Proton Ceramic Electrolysers (PCEs) Vigen 4 , E. M.L. Fontaine 1 , C. Denonville 1 , R. Strandbakke 2 , J.M. Serra 3 , D.R. Beeaff 4 , C. Vøllestad 2 , T. Norby 2 1 SINTEF Materials and Chemistry, 2 University of Oslo, 3 CSIC, 4 CoorsTek Membrane Sciences AS  Why PCE?  Processing & performance  Up-scaling of tubular PCEs

High temperature electrolysis enables utilization of waste heat resources ΔH 2H 2 + O 2 2H 2 O PCE SOE

Key differences between SOE and PCE - advantages and challenges  Solid Oxide Electrolysers  Well proven technology U 4e - SOEC  Scalable production  High current densities at thermo-neutral voltage 2H 2 O  Long term stability challenges 600-800°C  Delamination of O 2 -electrode 2O 2- O 2  Oxidation and degradation of Ni-electrode with high steam contents and/or low currents 2H 2  High temperatures  Proton Ceramic Electrolysers U 4e - PCEC  Less mature technology 2H 2 O  Fabrication and processing challenges  Produces dry H 2 directly 2H 2  Potentially intermediate temperatures 4H + 400-700°C  Slow O 2 -electrode kinetics O 2

High temperature electrolyser with novel proton ceramic tubular modules (2014-2017) Development of tubular 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 - cathode supported H + H + H + e - e - e - O 2 electrolyte cell O 2- H + H + H + BZY H + BZY H + BZY H + e - Conductor Protonic conductor Mixed Oxygen ion-electronic conductor nanoparticles Development and Single tube module optimization of anodes development and and current collection testing Multi-tube module testing Aim: 1kW demo Process integration and evaluation

Tubular half-cell production Wet milling of precursors Extrusion of BZCY-NiO support Spray- or dip-coating Dip-coating suspensions NiO based paste Solid State Reactive Sintering

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 40 microns 1670 ° C – 6h

Development of new anode materials T ( ° C) Ba 1-x Gd 0.8 La 0.2+x Co 2 O 6- δ (BGLC) displays best 800 600 400 PCE O 2 -H 2 O-electrode performance 2 100 (symmetrical disk samples) T ( ° C) 1 10 750 700 650 600 550 500 450 400 350 1.5 2 )) Log( R p,app ( Ω cm 2 ) R p,app ( Ω cm 0 1 1.0 X = 0.1 2 ) 0.5 log (( R p ( Ω cm X = 0.5 X = 0* -1 0.1 0.0 X = 0.3 GBCF / BZCY BSCF / BCY -0.5 Pr 2 NiO 4 / BCY 0.04 Ω cm LSCF / BCY 2 BGCF / BCY -2 0.01 -1.0 BGLC (x=0) / BZCY BCZF -1.5 0.8 1.0 1.2 1.4 1.6 1.8 1.0 1.1 1.2 1.3 1.4 1.5 1.6 -1 ) 1000 / T (K -1 ) 1000/T (K

LSM/BZCY composite electrodes  Symmetrical cell LSM/BCZY 60/40 % vol.: T (ºC) Conditions: 800 750 700 650 600 3 Total P= 3 bar 10 LSM/BCZY27 60/40 vol.% Steam 75% LSM/BCZY27 60/40 vol% Infilt. Pr-Ce T = 700 ° C LSM/BCZY27 60/40 vol% Infilt.Pr 2 10 LSM/BCZY27 60/40 vol% Infilt. Zr 2 ) Infiltration Pr-Ce R p ( Ω ·cm Rp = 0.64 Ω ·cm 2 at 700 ° C 1 10 Infiltration Pr Rp = 0.33 Ω ·cm 2 at 700 ° C 0 10 Infiltration Zr Rp = 7.88 Ω ·cm 2 at 700 ° C -1 10 0,9 1 1,1 1,2 -1 ) 1000/T (K

Electrolysis tests of single cell p O 2 : 80 mbar 2.0 p H 2 O: 1.5 bar p H 2 : 300 mbar Potential (V) 1.5 700°C 650°C 600°C 550°C 1.0 0 50 100 150 200 250 -2 ) Current (mA cm

Electrode resistance an order of magnitude higher than expected values from button cell testing T ( ° C) 700 600 500 400 2 100 0.8 550 Tube segment 600 1.5 bar steam 0.6 600 (x =0.5) 1 10 650 2 )) 0.4 2 )) 700 Log(Rp ( Ω cm 2 ) log( R p ( Ω cm 2 ) 700 (x = 0.5) Rp ( Ω cm R p ( Ω cm 0.2 0 1 R P (x = 0) 0.0 1 R P modelled R P modelled (x = 0) -1 0.1 -0.2 R P (x = 0.3) Target: R P (x = 0.5) -0.4 0.2 Ω cm 2 -2 0.01 0 50 100 1.0 1.2 1.4 1.6 -2 ) -1 ) I (mA cm 1000/T (K Button cell wet air

Scaling up – segmented-in-series tubes Higher tube voltage – lower tube current

Scaling up – stacking individual segments

Scaling up – “Printing in series”

Segmented-in-series tubular cells Novel interconnects H 2 O+O 2 electrode (PCEC anode) with H 2 O + O 2 flow integrated and patterned external current collection Novel external current collectors at closed/open ends of tube 3 Electrolyte 2 H 2 electrode (PCEC cathode) Porous support 1 H 2 flow BZY10 (SSRS or oxide) BZCY72 or BZCY (SSRS) + 2 3 1 or BZCY72 (SSRS or BZY10 (SSRS or sintering aid + pore oxide) oxide) formers + NiO

Manufacturing process Clean room activities 20 cm Annealing of Production of tubes Dip-coating Powder Pastes tubes (hang- by extrusion and conditioning preparation of tubes firing) collars • Milling of SSRS • Drying in air (organic • Drying Hang-firing of cells precursors and based coating) or at • Cutting oxide powders 60°C for water based • Masking and coating • Drying suspensions • Sieving • Batching 3 cm Slurries preparation Green support coated with cathode (green) and electrolyte (white) layers • Water based slurry for SSRS mixtures • Organic based slurries for oxide mixtures Green supports with electrodes

Optimized processing parameters for multi-layer sintering 300 µ m NiO- NiO- BZCY NiO- BZCY Support Support BZC BZC electrolyte BZC electrolyte Y Y Y 30 µ m 22

Conclusions  High temperature proton ceramic electrolysers can produce dry, pressurized hydrogen  Processing and manufacturing of tubular half cells is now well established  State-of-the-art electrolyser anodes are developed on button cell scale Deposition and firing protocols for tubular cells currently being developed   Segmented-in-series tubular cells are needed to reduce total current of tubes in real operational conditions

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.