WP 1: Fuel Cell Development 1 Strictly Confidential NMW Workpackage 1: Fuel Cell Development KTI Review Meeting, December 16, 2005 U. P. Muecke (NMW) and S. Rey-Mermet (EPFL) NTB INTERSTAATLICHE HOCHSCHULE FÜR TECHNIK BUCHS

WP 1: Fuel Cell Development 2 Strictly Confidential Project Management Thermal System Fuel Cell Gas Processing WP 1: Year 1 Milestones performance 200 mW/cm 550°C external electrical connections butane conversion rate > 90% post-combustor with gas oxidation > 98% battery expert industrial partner thermal insulation concept with T inside 550°C, T outside 50°C, <10 cm 3 structures for validation critical points thermal system demonstrator with simulated 2 W heat source

WP 1: Fuel Cell Development 3 Strictly Confidential Main Achievements after 6 Months First cell working at 12 mW / cm 2

WP 1: Fuel Cell Development 4 Strictly Confidential WP 1: Overview and Structure NMW NTB INTERSTAATLICHE HOCHSCHULE FÜR TECHNIK BUCHS Electrolyte Anode Cathode Spray pyrolysis Pulsed laser deposition Sputtering Cathode La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 Electrolyte Ce 0.8 Gd 0.2 O 1.9, Y 0.08 Zr 0.92 O 2-x Anode Ni-Ce 0.8 Gd 0.2 O 1.9 Substrate & Design Glas Ceramic Substrate & Design Silicon & Ni grid Anode Ni-Ce 0.8 Gd 0.2 O 1.9 Electrolyte Ce 0.8 Gd 0.2 O 1.9 Cathode La 0.7 Sr 0.3 CoO 3

WP 1: Fuel Cell Development 5 Strictly Confidential WP 1 Overview WP 1.1 Electrolyte –fabrication, electrical conductivity WP 1.2 Ni/CGO anode thin film –morphology, electrical conductivity, electrochemical characterization WP 1.3 LSCF cathode –morphology, electrical conductivity, electrochemical characterization WP 1.4 Microfabrication and contacting WP 1.5 PEN Integration and testing

WP 1: Fuel Cell Development 6 Strictly Confidential WP 1.1 Electrolyte Fabrication 200 nm Substrate in all cases sapphire. 200 nm Ce 0.8 Gd 0.2 O 1.9-x 200 nm Spray pyrolysis (SP) Pulsed laser deposition (PLD) dense and crack-free electrolyte films thickness nm sapphire Ce 0.8 Gd 0.2 O 1.9-x (sputtered Pt)

WP 1: Fuel Cell Development 7 Strictly Confidential WP 1.1 Electrolyte Properties Electrical conductivity Thermal stability ionic conductivity ~ 1 S/m at 700° C in air predominant ionic conductor for T < 600° C high thermal stability for T < 1100° C  no grain coarsening  no long term degradation Ce 0.8 Gd 0.2 O 1.9-x

WP 1: Fuel Cell Development 8 Strictly Confidential WP 1.1 Alternative Electrolyte - YSZ 1 µm Spray pyrolysis processing Electrical conductivity dense and crack-free electrolyte filmionic conductivity ~ 0.75 S/m at 700° C in air Y 0.08 Zr 0.92 O 2-x 1.18 eV

WP 1: Fuel Cell Development 9 Strictly Confidential WP 1.2 Electrolyte Conclusions Crack-free and dense CGO (SP and PLD) and YSZ (SP) films Ionic conductivity surpasses milestone Good thermal stability

WP 1: Fuel Cell Development 10 Strictly Confidential WP 1.2 Morphology of Ni/CGO Anode crack-free > 30% porosity nm thickness possible conventional Ni-YSZ cermet 200 nm ETH spray pyrolysis (top and cross) 200 nm EPFL sputtering (top and cross) 200 nm

WP 1: Fuel Cell Development 11 Strictly Confidential Conductivity of 60/40 Ni-CGO anode metallic conductivity °C literature: S/cm degradation: 0.85%/1000 hours milestone 100 S/cm Yin et al Pratihar et al. 2005

WP 1: Fuel Cell Development 12 Strictly Confidential Electrochemical Characterization - Intro RpRp I Total Cell (A vs. C) Half Cell (A vs. R) UpUp U Ni-CGO anode film Electrochemical Impedance Spectroscopy (EIS) polarization resistance

WP 1: Fuel Cell Development 13 Strictly Confidential Rp as a function of fuel gas H 2 O content Water vapor in the fuel decreases Rp in low frequency part H2OH2O

WP 1: Fuel Cell Development 14 Strictly Confidential Rp as a function of polarization Anodic overpotential => production of water I UpUp U i same effect as adding H 2 O to fuel => Rp decreases UpUp

WP 1: Fuel Cell Development 15 Strictly Confidential Rp - comparison water/polarization PO2PO2 water in anode gas P H 2 / P H 2 O applying overpotential U p R2R3 equivalent circuit fitting diffusion accounts for changes

WP 1: Fuel Cell Development 16 Strictly Confidential WP 1.2 Anode - Conclusions μm thick crack-free films with >30% porosity Conductivity surpasses milestone by factor 5 Conductivity stable over 1500 hours at 550°C Good electrochemical performance in dry and humidified gas Next: Improved low temperature sintering

WP 1: Fuel Cell Development 17 Strictly Confidential WP 1.3 Cathode Microstructure & Conductivity Porosity > 20 % is achieved by spray pyrolysis. A C Good electrical conductivity.

WP 1: Fuel Cell Development 18 Strictly Confidential WP 1.3 Cathode Phase Desired perovskite phase is obtained. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 ETH La 0.3 Sr 0.7 CoO 3 EPFL 2 Theta / deg J. ten Elshof, J. Boeijsma, Powder Diffr, 1996, 11 (3), 240. G.C. Kostogloudis, C. Ftikos, Solid State Ionics, 1999, 126 (1-2), 143.

WP 1: Fuel Cell Development 19 Strictly Confidential R p /  cm 2 WP 1.3 Cathode Performance J.A. Lane, P.H. Middleton, H. Fox, B.C.H. Steele, J.A. Kilner, In 2nd International Symposium on Ionic and Mixed Conducting Ceramics J.M. Ralph, A.C. Schoeler, M. Krumpelt, J. Mater. Sci., 2001, 36 (5), 1161.

WP 1: Fuel Cell Development 20 Strictly Confidential WP 1.3 Cathode Conclusions Crack-free films with >20% porosity achieved Good electrical conductivity Excellent electrochemical performance Next: Exploring new materials, e.g. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3

WP 1: Fuel Cell Development 21 Strictly Confidential WP 1.4 Microfabrication and Contacting Pt foturan glass foturan irradiated foturan glass anode electrolyte cathode contacted  -SOFC free-standing membrane etching 25 mm

WP 1: Fuel Cell Development 22 Strictly Confidential WP 1.5 PEN Integration and Testing Air Fuel EI Test rig with computer controlled gas supply and data acquisition Fuel Inert Oxygen Gas mixing unit Water Cell Exhaust

WP 1: Fuel Cell Development 23 Strictly Confidential WP 1.5 Measured Cell Performance T ~ 550°C OCV 170 mV Power density ~12 mW / cm 2 YSZ PLD Ni-CGO (SP) LSCF (SP)

WP 1: Fuel Cell Development 24 Strictly Confidential WP 1.5 Measured Cell Performance Small pores in the YSZ PLD electrolyte decrease performance Dense CGO SP electrolyte as sealing (to be included in cell) 400 nm YSZ PLD Ni-CGO (SP) LSCF (SP) CGO (SP) 2 new designs YSZ (PLD) Ni-CGO (SP) LSCF (SP) CGO (SP) Ni-CGO (SP) LSCF (SP)

WP 1: Fuel Cell Development 25 Strictly Confidential WP 1.5 Projected Cell Performance Projected cell performance based on results obtained for single layers today

WP 1: Fuel Cell Development 26 Strictly Confidential Actual design fabrication Membrane 2.4 cm Ni grid Current collector Contact cathode Contact anode

WP 1: Fuel Cell Development 27 Strictly Confidential Electrolyte membrane Ce 0.8 Gd 0.2 O 2 (CGO) Dense, polycrystalline film Ionic conductivity as in bulk ceramics Better than project specs

WP 1: Fuel Cell Development 28 Strictly Confidential Stress control of CGO-film Stress controlled by annealing in oxygen Freestanding membranes can be fabricated (2 mm)  Thermal stability with 150 nm: up to 300 °C 100 % Ar, 15 mT, RT Oxygen uptake

WP 1: Fuel Cell Development 29 Strictly Confidential Nickel Grid for membrane reinforcement and current collection 2. Current collector anode 4. CGO 9. Ni grid 100  m

WP 1: Fuel Cell Development 30 Strictly Confidential Free standing CGO membranes with nickel grid No annealing Annealing for low stress 100  m 50  m

WP 1: Fuel Cell Development 31 Strictly Confidential Summary Achievements Anode Cathode Membrane  > 100 S / cm R p < 1  cm 2  > 550 S / cm R p < 1  cm 2  > 0.5 S / cm to 500°CStable up 12 mW / cm 2

WP 1: Fuel Cell Development 32 Strictly Confidential Validation of Milestones and Deliverables WP 1.1: Electrolyte Month 3: - dense and crack-free electrolyte with composition CGO 80/20 (NMW, EPFL) - 500°C-800°C in air characterized;  > °C in air (NMW, EPFL) - microstructure characterized (NMW, EPFL) Month 6: - electrical characterization of free standing membrane (NMW, EPFL) - stress measurements as input for PEN design optimization (EPFL) - YSZ electrolytes characterized (NMW) WP 1.2: Anode Month 3: - crack-free Ni-CGO films,  > C, > 30% porosity in reduced state (NMW, EPFL) Month 6: - electrochemical characterization of NMW and EPFL films (NMW) - thermal stability and degradation f(T, t) (NMW, EPFL) - stress measurements (EPFL) Deliverables: Month 6: - selected samples NMW  EPFL for stress measurements: dimensions: 4`` or 1 cm x 3 cm, substrate: Si or Foturan Deliverables: Month 3: - selected samples from EPFL  NMW for electrochemical characterization: dimensions to be specified by U. Mücke - substrate: YSZ polished bulk pellet (from NMW) Month 6: - selected samples from NMW  EPFL for stress measurements: dimensions: 4`` or 1 cm x 3 cm, substrate: Si or Foturan           ongoing     ongoing

WP 1: Fuel Cell Development 33 Strictly Confidential Validation of Milestones and Deliverables WP 1.3: Cathode Month 3: - crack-free LSCF films,  > C, > 20% porosity (NMW, EPFL) Month 6: - electrochemical characterization of NMW and EPFL films (NMW) - stress measurements (EPFL) WP 1.4 Microfabrication and Electrical Contacting Month 3: - design of standard PEN and of electrical contacts available (NTB, NMW, EPFL) - first microstructured PEN elements ready for testing (NTB, NMW, EPFL) - proof of concept for Ni grid (EPFL) Month 6:- re-design of PEN element and electrical contacting (NTB, NMW, EPFL) - Integration of Ni grid in process flow (EPFL) Deliverables: Month 3: - selected samples from EPFL  NMW for electrochemical characterization: dimensions to be specified by D. Beckel - substrate: CGO polished bulk pellet (from NMW) Month 6: - selected samples from NMW  EPFL for stress measurements: dimensions: 4`` or 1 cm x 3 cm, substrate: Si or Foturan Deliverables: Month 3: - first microstructured PEN element NTB, EPFL  NMW for testing: dimensions to be specified by U. Mücke Month 6-12:- continuous supply of thin films and PEN elements for testing: NTB, NMW, EPFL     ongoing       

WP 1: Fuel Cell Development 34 Strictly Confidential Validation of Milestones and Deliverables WP 1.5: PEN Integration and Testing Month 3: - test rig for PEN characterization operating (NMW) Month 6: - first electochemical testing results of integrated PENs (NMW, EPFL, NTB)  

WP 1: Fuel Cell Development 35 Strictly Confidential First cell working at 12 mW / cm 2 Questions ?

WP 1: Fuel Cell Development 36 Strictly Confidential Long-term stability of 60/40 Ni-CGO anode -0.85%/1000 hours +0.36%/1000 hours milestone 100 S/cm T = 600°C testing