The Schatz Energy Research Center at California State University at Humboldt stated the following in its factsheet “Frequently Asked Questions About Fuel Cells,” available at www.schatzlab.org (accessed Dec. 19, 2008):
“A fuel cell is an electrochemical engine that converts the chemical energy of a fuel directly to electricity. Almost always the fuel is hydrogen or a hydrogen rich gas mixture. The fuel cell reaction is: Hydrogen + Oxygen (from the air) = Electricity + Water + Heat.”
The Smithsonian National Museum of American History stated the following in its article “Fuel Cell Basics,” available at www.americanhistory.si.edu (accessed Dec. 19, 2008):
“A fuel cell is a device that generates electricity by a chemical reaction. Every fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes.
Every fuel cell also has an electrolyte, which carries electrically charged particles from one electrode to the other, and a catalyst, which speeds the reactions at the electrodes.
Hydrogen is the basic fuel, but fuel cells also require oxygen. One great appeal of fuel cells is that they generate electricity with very little pollution—much of the hydrogen and oxygen used in generating electricity ultimately combine to form a harmless byproduct, namely water.”
The National Fuel Cell Research Center at the University of California at Irvine stated in its article “What is a Fuel Cell and How Does It Work,” published at www.nfcrc.uci.edu (accessed Dec. 19, 2008):
“Fuel cells are electrochemical devices that convert a fuel's chemical energy directly to electrical energy with high efficiency. With no internal moving parts, fuel cells operate similar to batteries. An important difference is that batteries store energy, while fuel cells can produce electricity continuously as long as fuel and air are supplied.
Fuel Cell diagram from the Schatz Energy Research Center (accessed Dec. 19, 2008)
Fuel cells electrochemically combine a fuel (typically hydrogen) and an oxidant without burning, thereby dispensing with the inefficiencies and pollution of traditional energy conversion systems.
Fuel cells forego the traditional fuel-to-electricity production route common in modern power production, which consists of heat extraction from fuel, conversion of heat to mechanical energy and, finally, transformation of mechanical energy into electrical energy...
Fuel cells function on the principal of electrolytic charge exchange between a positively charged anode plate and a negatively charged cathode plate. When hydrogen is used as the basic fuel, 'reverse hydrolysis' occurs, yielding only water and heat as byproducts while converting chemical energy into electricity.”
The California Fuel Cell Partnership stated the following in its factsheet “What Is a Fuel Cell,” available at www.fuelcellpartnership.org (accessed Dec. 19, 2008)
“A fuel cell is an electrochemical device that produces electricity…without combustion. Hydrogen fuel (which can be obtained from water or from hydrocarbon sources such as natural gas, methanol or petroleum products) is combined with oxygen (from the air) to produce electrical energy…
A Proton Exchange Membrane (PEM) fuel cell is comprised of a plastic membrane coated with a catalyst on both sides and sandwiched between two electrode plates. Hydrogen (from a fuel tank) and oxygen (from the air) are fed through channels in the plates on opposite sides of the membrane. The hydrogen and oxygen atoms are attracted to each other, but only the proton part of the hydrogen atom can pass through the membrane to reach the oxygen. The electron has to take the long way around the membrane to reach the oxygen atom—creating an electric current in the process. The electron is eventually reunited with the proton and an oxygen atom to create water (H 2O)…
[T]here are several types of fuel cells. Vehicles commonly use a Proton Exchange Membrane (PEM) fuel cell, sometimes referred to as a Polymer Electrolyte Membrane fuel cell…Other types of fuel cells can be used for stationary sources that generate heat and electricity for buildings. Fuel cells are also being designed for use in portable devices such as laptops and mobile phones.”
The US Department of Energy Office of Energy Efficiency and Renewable Energy stated the following on the webpage “Fuel Cells,” available on the Hydrogen, Fuel Cells and Infrastructure Technologies Program section of its website (accessed Dec. 19, 2008):
“A fuel cell is a device that uses hydrogen (or hydrogen-rich fuel) and oxygen to create electricity by an electrochemical process. A single fuel cell consists of an electrolyte and two catalyst-coated electrodes (a porous anode and cathode). While there are different fuel cell types, all work on the same principle:
Hydrogen, or a hydrogen-rich fuel, is fed to the anode where a catalyst separates hydrogen's negatively charged electrons from positively charged ions (protons).
At the cathode, oxygen combines with electrons and, in some cases, with species such as protons or water, resulting in water or hydroxide ions, respectively.
For polymer electrolyte membrane and phosphoric acid fuel cells, protons move through the electrolyte to the cathode to combine with oxygen and electrons, producing water and heat.
For alkaline, molten carbonate, and solid oxide fuel cells, negative ions travel through the electrolyte to the anode where they combine with hydrogen to generate water and electrons.
The electrons from the anode side of the cell cannot pass through the electrolyte to the positively charged cathode; they must travel around it via an electrical circuit to reach the other side of the cell. This movement of electrons is an electrical current.”