1. High-Performance Fuel Cell Membranes Arumugam Manthiram The University of Texas at Austin

2. Energy outlook Energy is the greatest challenge facing humankind in the 21st century. Energy is the greatest challenge facing humankind in the 21st century. Important societal issue, impacts our way of life, the economy, national security, environment, and our health Important societal issue, impacts our way of life, the economy, national security, environment, and our health Current production cannot keep up with rising needs. Current production cannot keep up with rising needs. Alternative, sustainable, clean energy technologies are necessary. Alternative, sustainable, clean energy technologies are necessary. Annual Energy Outlook 2005, http://www.eia.doe.gov/oiaf/aeo/index.html

3. Why fuel cells? Modular, local Watt to megawatt power High power density and high efficiency (60%) No Carnot limitation Environmentally friendly Clean energy Quiet Hea t Electrolyte AnodeCathode e-e- 2e - Air 1/2O21/2O2 H + conductor H2OH2O 2e - + H2H2 2H + H2OH2O H2H2 e-e- ~ 0.7 V H 2 + ½ O 2 H 2 O + Electricity + Heat Catalyst < 100°C

4. Current technology commercialization is hampered by high cost, durability, and operability problems linked to materials issues (primarily membranes and catalysts) Operating temperature <100°C Humidification requirements Methanol crossover High cost Electrolyte AnodeCathode 2e - 1/2O21/2O2 H + or O 2- conductor H2OH2O 2e - + H2H2 2H + CH 3 OH or CH 4 Challenges of current fuel cell technologies Membrane High cost of Nafion membrane Limited to < 100°C as it needs to be wet Complex external humidification system Methanol crossover from anode to cathode Degradation (peroxide attack, F- release) Catalyst Expensive, less abundant Pt catalyst Poisoning of Pt by CO at top < 100°C Poor utilization of Pt (80% waste) Catalyst/support instability/degradation Solution: Explore alternative, new materials

5. New polymeric membranes Consists of an acidic and basic polymers Proton conduction based on acid-base interactions May not need water for proton conduction Permits operation above 100°C Lower methanol permeability Higher power density Lower platinum catalyst loading Cost savings (up to 90% reduction)

6. Applications of fuel cells Hydrogen fuel cells for stationary power and automobiles Direct methanol fuel cell could replace lithium-ion batteries in portables Charging with an electrical outlet can be eliminated 10X higher energy density by volume than lithium-ion batteries 30X higher energy density by weight than lithium-ion batteries 50% weight saving in laptop (340 Wh/kg vs. lithium-ions 160 Wh/kg)