BY ALLEN DEARMOND AND LAUREN CUMMINGS

Generates electric power using a fuel and an oxidant

Unlike a battery, chemicals are not stored in the fuel cell; they must be replenished

Possible fuel sources: hydrogen, alcohols, hydrocarbons, gasoline Possible oxidants: oxygen, chlorine, chlorine dioxide Refueling of an internal combustion engine, efficient and quiet like a battery

Polymer Electrolyte Membrane (PEM) Fuel Cells

Direct Methanol Fuel Cells Alkaline Fuel Cells Phosphoric Acid Fuel Cells Molten Carbonate Fuel Cells Solid Oxide Fuel Cells Regenerative Fuel Cells

Anode (-) and Cathode (+) on each side of the fuel cell, divided by an electrolyte

Hydrogen gas is channeled through anode side; oxygen passes through cathode

Platinum catalyst oxidizes hydrogen atoms into H+ and electrons

Electrons pass along external circuit; conduct electricity before entering cathode

Electrolyte allows H+ to pass into the cathode In cathode, catalyst combines H+ , O2- and

electrons, forming H2O and heat

Anode:2H2 => 4H+ + 4e-

Cathode: O2 + 4H+ + 4e- => 2H2O

Net Reaction:2H2 + O2 => 2H2O

Exact opposite of electrolysis

Catalyst: increases rate of reaction without being consumed in the process

Platinum is main catalyst used in PEM fuel cells

Platinum is expensive and highly sensitive to poisoning

New platinum/ruthenium catalysts being researched for use in hydrogen fuel cells

Reaction requires lower temperatures and high humidity and pressure

Little-to-no pollution, doesn’t need to be recharged

2500 fuel cell systems have been installed globally

Used to power landfills and water treatment plants

50 fuel cell buses Every major automotive manufacturer has

designed a fuel cell-powered vehicle Mercedes-Benz projects 40% efficiency in

compact cars running on Hydrogen fuel cells Hydrogen Fuel Initiative (2003)

Fuel cells require specific humidity, pressure, etc.

Catalysts are pricey and sensitive to poisoning

Difficult to produce hydrogen Difficult to store optimum amounts of

Hydrogen If fuels other than hydrogen are used,

some greenhouse gasses are emitted Very few cars currently running on

hydrogen

Used to power personal electronic devices: cell phones, iPods, laptops

Enough energy to run for days, or weeks (instead of hours)

Potentially power all cars, airplanes, ships, etc. 60 million tons of carbon dioxide could be

eliminated from yearly greenhouse gas production

Development of cheaper and more reliable catalysts

Higher demand = cheaper

Economic crisis has greatly slowed technological advancements

Past predictions for 2010 seem unlikely Hydrogen cannot be the only alternative

fuel source to solve the energy crisis Many more years of research before

mass production will be possible

Hydrogen fuel cells are efficient, and clean

Also expensive, and require specific humidity, temperature, pressure

With more technological advancements, could be used in mass production for various applications

Not an instant fix for the energy crisis, but definitely a major component

Basic Elements: Fuel for the Future. Miramar High School. 3 March 2009.

<http://library.thinkquest.org/04apr/00215/energy/fuel_cells/fuel_cells.htm>

Fuel Cells. Princeton University. 3 March 2009. <http://www.princeton.edu/~chm333/2002/spring/FuelCells/>

Fuel Cells. U.S. Department of Energy. 9 March 2009. <http://www1.eere.energy.gov/

hydrogenandfuelcells/fu elcells/fc_types.html> Hydrogen.gov United States Government. 10 March

2009. <http://www.hydrogen.gov>. Nice, Karim and Jonathan Strickland. “How Fuel Cells

Work.” 18 September 2000. How Stuff Works.com. <http://www.howstuffworks.com/fuel-cell.htm 3

March 2009>.