Next Generation Fuel Cells:
Anion Exchange Membrane Fuel Cells
Image: Quarternary Amine Polysulfone
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
Presented By Jerry Gilligan
Primary Source Material
Lu, S., Pan, J., Huang, A., Zhuang, L., and Lu, J.
“Alkaline polymer electrolyte fuel cells completely
free of noble metal catalysts.” Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
The Transportation Problem
Hydrocarbon
O2
Fuel
Internal
Combustion
Engine
Heat
Work
~28% of US energy consumption is in the
transportation sector, and 95% of that
demand is met by petroleum based
hydrocarbon fuels.
Heat Loss CO2
Image: Jaguar XK
Apple Inc.; 2011. “Desktop Images.”
www.apple.com
Source: US EIA
US EIA; 2011. US Energy Info.
Admin. www.eia.gov/aer
Why Fuel Cells?
Oxidizing Reducing
Agent
Agent
Hydrocarbon
O2
Fuel
Internal
Combustion
Engine
Heat Loss CO2
Heat
Work
Fuel
Cell
Electrical
Work
H2O
Zaidi, J. et. al.; 2010.
Why Fuel Cells?
Oxidizing Reducing
Agent
Agent
Hydrocarbon
O2
Fuel
Internal
Combustion
Engine
Heat
Work
Fuel
Cell
Inefficient
CO2 Producer
Hydrocarbon Consumer
Heat Loss CO2
Electrical
Work
More Efficient
Benign Byproducts
Abundant Fuel
H2O
Zaidi, J. et. al.; 2010.
Efficiency Comparison
Oxidizing Reducing
Agent
Agent
Hydrocarbon
O2
Fuel
Internal
Combustion
Engine
Heat
Work
Fuel
Cell
Energy Efficiency
Theoretical: 37% (Steel)
Real: 20% (Steel)
Heat Loss CO2
Electrical
Work
Energy Efficiency
Theoretical: 60-70%
Real: 50-60%
H2O
Zaidi, J. et. al.; 2010.
Inefficiency Sources
Oxidizing Reducing
Agent
Agent
Hydrocarbon
O2
Fuel
Internal
Combustion
Engine
Heat Loss
Heat
Work
Fuel
Cell
Energy Efficiency
Theoretical: 37% (Steel)
Real: 20% (Steel)
Heat Loss CO2
Resistance
Electrical
Work
Energy Efficiency
Theoretical: 60-70%
Real: 50-60%
H2O
Zaidi, J. et. al.; 2010.
The Fuel Cell Vehicle
Image: Fuel Cell Equinox
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
Refuels at Pumping Stations, Runs on Air and
Hydrogen, and Has Momentary Output
Required for Merging.
Types of Fuel Cells
SOFC – Solid Oxide
MCFC – Molten Carbonate
AFC – Alkaline/Anionic
PAFC – Phosphoric Acid
PEMFC – Polymer Electrolyte
Membrane
Image: Fuels and Fuel Cells
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
Alkaline Fuel Cells
SOFC – Solid Oxide
MCFC – Molten Carbonate
AFC – Alkaline/Anionic
PAFC – Phosphoric Acid
PEMFC – Polymer Electrolyte
Membrane
Image: Fuels and Fuel Cells
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
AFCs vs PEMFCs
AFC – Alkaline Fuel Cell
Requires no Pt/Noble Metal
Catalyst
More Efficient
Carbonate Poisoning Problem
PEMFC – Proton Exchange
Membrane Fuel Cell
Requires Pt Catalyst
Image: Fuels and Fuel Cells
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
Known Exchange Membranes
with High Conductivity
AFCs: Alkaline Reactions
Anode (ox): 2 H2 + 4 OH- → 4 H2O + 4eRaney Ni Catalyst
Cathode (red): O2 + 2 H2O + 4e- → 4 OHAg Catalyst
Overall: O2 + 2H2 → 2H2O
AFC Applications
Current Uses:
Submarines
Military Applications
NASA’s Space Shuttle
Future NASA Craft
The technology needs to
overcome significant
hurdles to break in to the
commercial transportation
marketplace.
Image: Shuttle AMFC Cell Stack
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
AFCs vs PEMFCs
AFC – Alkaline Fuel Cell
Requires no Pt/Noble Metal
Catalyst
Carbonate Poisoning Problem
PEMFC – Proton Exchange
Membrane Fuel Cell
Requires Pt Catalyst
Known Exchange Membranes
with High Conductivity
Image: Fuels and Fuel Cells
Fray, D.; 2011. “DoITPoMS: Fuel Cells.”
University of Cambridge.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
AFCs: CO2 Poisoning Mechanism
Pure O2
From O2 (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3-
[HCO3-] < [OH-]
2 H2 + 4 OH- → 4 H2O + 4e-
No CO2 Poisoning
AFCs: CO2 Poisoning Mechanism
Pure O2
From O2 (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3-
[HCO3-] < [OH-]
2 H2 + 4 OH- → 4 H2O + 4e-
No CO2 Poisoning
AFCs: CO2 Poisoning Mechanism
Air
From Air (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3[HCO3-] > [OH-]
2 HCO3- → 2 OH- + 2 CO2
H2 + 2 OH- → 2e- + 2H2O
CO2 Poisoning
Ph Change, Reduced Operation,
Precipitation of Carbonates
AFCs: CO2 Poisoning Mechanism
Air
From Air (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3[HCO3-] > [OH-]
2 HCO3- → 2 OH- + 2 CO2
H2 + 2 OH- → 2e- + 2H2O
CO2 Poisoning
Ph Change, Reduced Operation,
Precipitation of Carbonates
AFCs: CO2 Poisoning Mechanism
Air
From Air (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3[HCO3-] > [OH-]
2 HCO3- → 2 OH- + 2 CO2
H2 + 2 OH- → 2e- + 2H2O
CO2 Poisoning
Ph Change, Reduced Operation,
Precipitation of Carbonates
AFCs: CO2 Poisoning Mechanism
Air
From Air (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3[HCO3-] > [OH-]
2 HCO3- → 2 OH- + 2 CO2
H2 + 2 OH- → 2e- + 2H2O
CO2 Poisoning
Ph Change, Reduced Operation,
Precipitation of Carbonates
AFCs: CO2 Poisoning Mechanism
Air
From Air (Cathode):
Membrane Crossover:
To Air (Anode):
O2 + 2 H2O + 4e- → 4 OHCO2 + OH- → HCO3[HCO3-] > [OH-]
2 HCO3- → 2 OH- + 2 CO2
H2 + 2 OH- → 2e- + 2H2O
CO2 Poisoning
Ph Change, Reduced Operation,
Precipitation of Carbonates
Anion Exchange Membrane Fuel Cell
AEMFC
Does not require Pt Catalyst
Reduced CO2 Poisoning Effect
New Membranes!
Image: APEFC Schematic
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
QAPS Membrane
Quaternary
Ammonium
Polysulfone
Image: QAPS Structure
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
OH- Conduction
Coordination of
OH-
Quaternary
Ammonium
Polysulfone
OH-
Image: QAPS Structure
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
Fuel Cell Performance
Membrane Conductivity – 10-2 S/cm
Power Density – 50 mW/cm2
Temperature - 60°C
Operation Time - >100 hrs no Degradation
Image: APEFC Schematic
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
Fuel Cell Performance
Membrane Conductivity – 10-2 S/cm
Power Density – 50 mW/cm2
Temperature - 60°C
Operation Time - >100 hrs no Degradation
Membrane Swelling
Image: APEFC Schematic
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
A Green Chemistry
12 Principles
1. Waste Prevention
2. Atom Efficiency
3. Human and Environmental Safety
4. Nontoxic
5. Reduce Auxiliary Substances
6. Minimize Energy Requirements
7. Renewable Feedstock
8. Reduce Derivatives
9. Use Catalytic Reagents
10. Low Environmental Lifetimes
11. Analytical Monitoring of Hazardous Substances
12. Minimize Potential for Danger
Image: APEFC Schematic
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
A Green Chemistry
12 Principles
1. Waste Prevention
2. Atom Efficiency
3. Human and Environmental Safety
4. Nontoxic
5. Reduce Auxiliary Substances
6. Minimize Energy Requirements
7. Renewable Feedstock
8. Reduce Derivatives
9. Use Catalytic Reagents
10. Low Environmental Lifetimes
11. Analytical Monitoring of Hazardous Substances
12. Minimize Potential for Danger
Image: APEFC Schematic
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
Next Generation Fuel Cells:
Anion Exchange Membrane Fuel Cells
Works Cited
1. Fray, D.; 2011. “DoITPoMS: Fuel Cells.” University of
Cambridge Press.
http://www.doitpoms.ac.uk/tlplib/fuel-cells/printall.php
2. Lu, S., Pan, J., Huang, A., Zhuang, L., and Lu, J; 2008.
“Alkaline polymer electrolyte fuel cells completely
free of noble metal catalysts.” Proc. Natl. Acad.
Sci. 105, 52; 20611-20614.
3. Gasteiger, H. and Schmidt, T.; 2011 “ECS PEFC Short
Course.” Boston, ECS.
4. US EIA; 2011. “Annual Energy Review 2010.” US Energy
Info.Admin. www.eia.gov/aer
5. Zaidi, J. et. al.; 2010. Polymer Membranes for Fuel
Cells. Springer. New York, NY.
Image: Quarternary Amine Polysulfone
Lu et. al.; 2008. Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.
Presented By Jerry Gilligan
Primary Source Material
Lu, S., Pan, J., Huang, A., Zhuang, L., and Lu, J.
“Alkaline polymer electrolyte fuel cells completely
free of noble metal catalysts.” Proc. Natl. Acad.
Sci. 2008. 105, 52; 20611-20614.