B Y A LLEN D E A RMOND AND L AUREN C UMMINGS

 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 +, O 2- and electrons, forming H 2 O and heat

 Anode: 2H 2 => 4H + + 4e -  Cathode: O 2 + 4H + + 4e - => 2H 2 O  Net Reaction: 2H 2 + O 2 => 2H 2 O  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  Fuel Cells. Princeton University. 3 March  Fuel Cells. U.S. Department of Energy. 9 March  Hydrogen.gov United States Government. 10 March  Nice, Karim and Jonathan Strickland. “How Fuel Cells Work.” 18 September How Stuff Works.com..