Fuel cells
A fuel cell is a type of power generation that uses chemical reactions to create electricity. It differs from batteries in that reactants are supplied externally. Most fuel cells use hydrogen as a fuel source and have minimal emissions; electricity and water are usually the only products of the fuel cell’s chemical reactions.
Contents
Parts of a fuel cell
A fuel cell is comprised of four primary parts: the anode, the cathode, the proton exchange membrane, and the catalyst.[1]
- The anode and the cathode are electrodes which carry a positive or negative charge; also known as Gas Diffusion Layers (GDL). The anode is negatively charged and cathode is positively charged. They are placed on opposite sides of the fuel cell, so that the proton exchange membrane and the catalyst layers are sandwiched in-between.
- The Proton Exchange Membrane (PEM), sometimes referred to as a polymer electrolyte membrane or simply the electrolyte, is a thin piece of material that looks similar to ordinary kitchen plastic wrap. It is treated to allow protons (positively charged particles) to be conducted through the material, but blocks the electrons (negatively charged particles) from taking the same path as the protons. Scientists are working to produce different types of fuel cells with differing characteristics. The PEM is usually the primary component changed between the different types of fuel cells being researched, so it is often simply referred to as the electrolyte.[2]
- The catalyst layers are placed in-between the PEM and the electrodes: one layer between the PEM and the anode and one between the PEM and the cathode. The catalyst is made of microscopic particles of platinum are placed on a carbon support and mixed with an ion-conducting polymer (known as an ionomer). The layer next to the anode separates hydrogen atoms into electrons and protons while the layer next to the cathode reacts with oxygen and the protons that traveled through the PEM to form water.[3]
How fuel cells work
In a fuel cell, hydrogen is fed into the system next to the anode, where the catalyst separates the electron from the rest of the hydrogen molecule. The hydrogen molecule, which no longer has any electrons and is thus positively charged, travels through the PEM where it meets up with the oxygen that has entered near the cathode. The hydrogen and oxygen combine to make a water byproduct. Meanwhile, the free electron, not attached to any molecule, is channeled through an external circuit, creating a flow of electricity. As long as hydrogen and oxygen are being pumped into the fuel cell, it will continue to produce electricity.[4]
Fuel cell issues
Although fuel cells are much cleaner than conventional means of energy production, ongoing research is still working to make it a feasible option for everyday life. Scientists are currently working to reduce the cost of making the fuel cell, increasing performance and durability, and perfecting hydrogen storage, production, and delivery.
- The catalyst requires platinum in order to separate the electrons (which produce electricity) from the rest of the hydrogen molecule. This need for platinum is one of the largest costs of a fuel cell. Scientists are researching other materials that could replace platinum in the catalyst to hopefully reduce the costs of fuel cells.
- Researchers are constantly looking to improve the performance of various parts of the fuel cell. However, the greatest factor that needs improvement is durability. Scientists believe that fuel cells will one day be used in car all across the United States. However, in order for that to happen, the fuel cells need to be able to withstand varying humidity levels, freezing temperatures, thawing, and various other stresses. Scientists are working on finding way to make sure that all the fuel cell components are able to work properly in all different conditions.[5]
Hydrogen
Perhaps the largest obstacle in widespread fuel cell usage is the production and storage of hydrogen. Hydrogen fuel cells work best with pure hydrogen fueling them; however, pure hydrogen does not exist on its own on Earth in any quantity large enough to collect as fuel, it must be refined from other sources, such as water or natural gas. The refining process usually uses fossil fuels to produce hydrogen, which reduces the overall cleanliness of fuel cells.[6] Some fuel cells also use a fuel processor to convert hydrogen-rich conventional fuel into usable hydrogen for the fuel cells.[7]
See also
References
- ↑ Parts of a Fuel Cell | Department of Energy. (n.d.). Retrieved July 24, 2015, from http://www.energy.gov/eere/fuelcells/parts-fuel-cell
- ↑ Types of Fuel Cells | Department of Energy. (n.d.). Retrieved July 24, 2015, from http://www.energy.gov/eere/fuelcells/types-fuel-cells
- ↑ Parts of a Fuel Cell | Department of Energy. (n.d.). Retrieved July 24, 2015, from http://www.energy.gov/eere/fuelcells/parts-fuel-cell
- ↑ Fuel cells | Institute of Physics. (n.d.). Retrieved July 27, 2015, from http://www.iop.org/resources/topic/archive/fuel/
- ↑ Fuel Cells | Department of Energy. (n.d.). Retrieved July 24, 2015, from http://www.energy.gov/eere/fuelcells/fuel-cells
- ↑ Fuel cells | Institute of Physics. (n.d.). Retrieved July 27, 2015, from http://www.iop.org/resources/topic/archive/fuel/
- ↑ Fuel Cell Systems | Department of Energy. (n.d.). Retrieved July 24, 2015, from http://www.energy.gov/eere/fuelcells/fuel-cell-systems
External links
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