How Fuel Cells Work

Courtesy of U.S. Department of Energy, Argonne National Laboratory 

Department of Energy. Fuel Cell Basics. http //www.eere.energy.gov/hydrogenandfuelcells/fuelcells/baslcs.html 

Argonne National Laboratory. Argonne s Fuel-Flexible Reformer. http //www.cmt.anl.gov/science-technology/fuelreformer.shtml 

Energy Educators of Ontario Energy Fact Sheet. Fuel Cells. http //www.iclei.org/EFACTS/FUELCELL.HTM 

2) Electrons split away from hydrogen flow through anode to external electric load. 

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Tower, Stephen. All About Electrochemistry. Available online. URL http //www.cheml.com/acad/webtext/elchem/. Accessed May 28, 2009. Part of a virtual chemistry textbook, this excellent resource explains the basics of electrochemistry, which is important in understanding how fuel cells work. Discussions include galvanic cells and electrodes, cell potentials and thermodynamics, the Nernst equation and its applications, batteries and fuel cells, electrochemical corrosion, and electrolytic cells and electrolysis. 

Nice, Karim. How Fuel Cells Work. Howstuffworks. Available online. URL http //www.howstuffworks.com/fuel-cell.htm. Accessed Dec. 17, 2006. 

For a more detailed explanation of how fuel cells work, see chapter 7. 

There are many types of different fuel cells however, for our purposes we will focus on proton exchange membrane (PEM) fuel cells because they are most applicable to automobiles. A PEM basically consists of an anode and cathode in a thin cell separated by a polymer membrane. There is a platinum catalyst, which is electrochemi-cally active. Also, of course, hydrogen and oxygen are in the circuit. Figure 10.1 illustrates the process of how fuel cells work. 

There is a useful video about how fuel cells work on the HowStuffWorks website http y/autp,hpwstuffwprks.cpm/ fuehceU.htm... 

How does a fuel cell work What are SOFC and PEM fuel cells ... 

FIGURE 4.24 Schematic illustration of how two different fuel cells work with pure hydrogen as fuel (left), and with methanol as fuel (right). (From Nunes S.P., Review on fuel cells. Presentation at EMS Summer School, NTNU, Trondheim, Norway, 2003. With permission.)... 

What is biocatalytic synthesis 26) How do fuel cells work (27) How can chemicals be produced from renewable resources 28) Why is the inexpensive production of levulinic acid important commercially 29) What is biodiesel 30)... 

On October 10, 2007, Gerhard Ertl of Germany received an amazing 71st birthday present, the Nobel Prize in Chemistry. His research in answering questions such as why iron rusts, how fuel cells function, and how catalysts work, helps to explain the reasons behind Earth s damaged ozone layer. Ertl s prize includes a gold medal, a diploma, and 10 million krona (Swedish) or about 1.5 million (U.S.). 

Practical fuel cell systems are very complex to design and build—especially small, rugged ones for cars, trucks, and buses, which must stand up to bumps and to temperature variations. (This is one reason why it took so long to put the first prototypes on the road.) But the basic principle of how a fuel cell works is fairly straightforward. 

How a fuel cell works As in other voltaic cells, a fuel cell has an anode and a cathode and requires an electrolyte so that ions can migrate between electrodes. A common electrolyte in a fuel cell is an alkaline solution of potassium hydroxide. Each electrode is a hollow chamber of porous carbon walls that allows contact between the inner chamber and the electrolyte surrounding it. The following oxidation half-reaction takes place at the anode. 

Many statements and descriptions are plain and brief, but they are the crystallization of many years of my experience and research. You ll explore fundamental questions Will the catalyst particles be able to participate in the electrochemical reaction if they are fully covered by a thin ionomer film What can the limiting current density be based on the mass transport of air How severe will the voltage loss be if a thin layer of liquid water forms How can you quickly assess catalytic activity difference based on voltage difference in V-I curves How can a direct methanol fuel cell work using neat methanol How high can H2and O2 gases be pressurized within a PEM electrolyzer ... 

Fuel cell basics Fuel cell overview How file cells work... 

Use chemical equations to explain how the hydrogen-oxygen fuel cell works. 

The book is, in many respects, unique. First of all, everywhere it starts from physics, oriented on physical understanding of how all components of fuel cells work and, most importantly, how they work together. Indeed, fuel cells are very interesting objects for physics—and both authors are physicists (with all of their degrees received in physics). 

To better understand how a PEM fuel cell works, it is necessary to grasp the fundamentals of PEM fuel cells, including their cell structure and the thermodynamics and kinetics of fuel cell electrochemical reactions. In the following sections of this chapter, the fundamentals of H2/air PEM fuel cells will be discussed in detail. 

Leger JM, Rousseau S, Coutanceau C, Hahn E, Lamy C. 2(X)5. How bimetallic electrocatalysts does work for reactions involved in fuel cells Example of ethanol oxidation and comparison to methanol. Electrochim Acta 50 5118-5125. 

However, after implementing the water balance measurements, they were not able to observe a significant difference on the net water drag coefficient for a fuel cell with a cathode MPL and an anode without an MPL compared to a cell without any MPLs. It is important to note that they were able to observe that the MPL does in fact improve the fuel cell performance and stability when operating at constant conditions (i.e., the voltage fluctuations are significantly reduced when the cathode DL has an MPL). These results do not correlate with the observations presented earlier thus, more experimental work is necessary to investigate the process behind how the MPL helps the performance of the fuel cell. 

In 2000 and 2001, fuel-cell models were produced by the dozens. These models were typically more complex and focused on such effects as two-phase flow ° where liquid-water transport was incorporated. The work of Wang and co-workers was at the forefront of those models treating two-phase flow comprehensively. The liquid-water flow was shown to be important in describing the overall transport in fuel cells. Other models in this time frame focused on multidimensional, transient, and more microscopic effects.The microscopic effects again focused on using an agglomerate approach in the fuel cell as well as how to model the membrane appropriately. 

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