1. Polttokennot Jorma Selkäinaho Aalto yliopisto

2. Fuel cells Fuel cell makes electricity directly from fuel Typical fuels H 2, CH 4, CH 3 OH Exhaust H 2 O Dream applications: - warehouse forklifts - submarines - space crafts

3. Proton exchange membrane FC H2 PEM - Ballard Power (Canada) - Nedstack (Netherlands) - Horizon Fuel Cell (Singapore) Direct Methanol FC - Smart Fuel Cells (Germany)

4. H2 PEM FC Anode 2*H 2 => 4*H + + 4*e - Platinum catalyst Proton conducting membrane (Nafion) Cathode O 2 + 4*e - + 4*H + + => 2*H 2 O CO is poison > 10 ppm Temperature 50-90 oC Current density 1000 mA/cm 2

5. H2 PEM FC Control objectives: - stack temperature - membrane humidity - electric power - avoiding catalyst flooding Price about 3000 eur/kW

6. Direct Methanol FC Anode CH 3 OH + H 2 O => 6*H + + 6*e - + CO 2 PtRu (An) and Pt (Ca) catalysts Nafion membrane Cathode 1.5*O 2 + 6*H + + 6*e - => 3*H 2 O CH 3 OH > 8% => CO poisoning

7. Alkaline electrolyte FC Anode 2*H 2 + 4*OH - => 4*H 2 O + 4*e - Ni (An) and NiO (Ca) catalysts OH - ion conducting electrolyte (KOH) Cathode O 2 + 4*e - + 2*H 2 O => 4*OH - CO 2 poisoning : 2*KOH + CO 2 => K 2 CO 3 + H 2 O Hydrocell (Finland -2012)

8. High Temperature FC Phosphoric acid FC Molten carbonate FC Solid oxide FC

9. Phosphoric acid FC Anode 2*H 2 => 4*H + + 4*e - Platinum catalyte Proton conducting electrolyte Cathode O 2 + 4*e - + 4*H + => 2*H 2 O H 3 PO 4 tolerates CO 2 Temperature 180-200 o C Lifetime 40.000 h

10. Phosphoric acid FC Cell voltage 600-800 mV Current density 150-400 mA/cm2 Stack power 50 kW – 11 MW Banks, hospitals etc (backup power) Commercial but expensive

11. Molten carbonate FC Anode 2*H 2 + 2*CO 3 2- => 2*H 2 O + 2*CO 2 +4*e - Ni (An) and NiO (Ca) catalysts CO3 2- conductor electrolyte Cathode O 2 + 2*CO 2 + 4*e - => 2*CO 3 2- Fuel H 2, CH 4 or CO Temperature 650 o C

12. Molten carbonate FC Cell voltage 750-900 mV Current density 100-200 mA/cm2 Fuel Cell Energy 2 MW MC Power corporation 250 kW Hitachi-Mitsubishi-Toshiba 1 MW Pre commercial demonstrations

13. Solid oxide FC Anode 2*H 2 + 2*O - => 2*H 2 O + 4*e - Ni catalyte O = ion conductor electrolyte Cathode O 2 + 4*e - => 2*O = Fuel H 2, CH 4 or CO Anode 2*CO + 2*O = => 2*CO 2 + 4*e - Cathode O 2 + 4*e - => 2*O =

14. Solid oxide FC Temperature 750-900 oC Topsoe (Denmark) stack manufacturer Pre commercial demonstrations Wärtsilä 5-50 kW (Finland) Bloom energy (USA)

15. Solid oxide FC Control targets - slow warming from 20oC to 750 oC - minimize temperature variations - CH4 autoreformation - power Price about 10.000 eur/kW