Fuel cells have received a lot of attention lately from the media, the public, and even some politicians. In 2003, President Bush announced the Hydrogen Fuel Initiative during the State of the Union Address. His main goal was that one day we can use hydrogen as fuel for our cars. Is this achievable? Well, I will take my time in this article to explain how fuel cells and their basic components work.
These devices convert chemical energy into electrical energy. They use hydrogen and oxygen as chemicals to produce electricity and water. This makes them a good source of energy. These cells have four basic components which include; an anode, a cathode, an electrolyte and a catalyst. I will describe each of them in detail below.
the anode
This is the negative element of the cell. It conducts the electrons that are released from the hydrogen molecules to an external circuit. It also disperses hydrogen gas evenly over the catalyst surface.
the cathode
This is the positive element of the cell. It funnels electrons from the external circuit to the catalyst, where they recombine with hydrogen and oxygen ions to form water. It also distributes oxygen to the catalyst surface.
the electrolyte
This is the proton exchange membrane. This is a special material that only conducts positively charged ions. The membrane is there to block the electrons. This membrane must always be hydrated in order to function and remain stable.
the catalyst
This is the material that facilitates the reaction of oxygen and hydrogen. It is made of platinum nanoparticles that are coated with a thin layer of carbon paper or cloth. Catalysts are generally made rough and porous so that the maximum surface area of the platinum can be exposed to hydrogen or oxygen. The platinum side of the catalyst faces the membrane mentioned above.
How do fuel cells work?
Pressurized hydrogen gas enters the cell from the anode side of the cell. This gas is channeled through the catalyst by pressure. When hydrogen comes into contact with the platinum in the catalyst, it splits into two hydrogen ions and two electrons. These electrons are conducted through the anode, where they are taken to the external circuit and return to the cathode side of the cell. The released electrons produce the electricity needed to turn the motor.
On the cathode side of the cell, oxygen is forced across the catalyst, where it splits into two oxygen atoms. These atoms have a strong negative charge. This negative charge attracts the two hydrogen ions across the membrane. When hydrogen and oxygen combine, they form water. This makes the cells friendly to the environment.
This reaction in a single cell typically produces 0.7 volts. To increase the voltage, many separate cells must be combined to form a fuel cell stack. Depending on what the cell will be used for, different combinations will be used to produce different voltages.
It is important to note that there are many types of fuel cells that work differently than what I have described above. However, this is the basics of how they work. Other fuel cells split hydrogen gas into HHO or oxyhydrogen gas, which is used to increase the power of car engines.
