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Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable fuel-cell applications. Their distinguishing features include lower temperature/pressure ranges (50 to ...
Whereas the common PEM fuel cell, also called Low Temperature Proton Exchange Membrane fuel cell (LT-PEM), must usually be operated with hydrogen with high purity of more than 99.9 % the HT-PEM fuel cell is less sensitive to impurities and thus is typically operated with reformate gas with hydrogen concentration of about 50 to 75 %.
The primary application of proton-exchange membranes is in PEM fuel cells. These fuel cells have a wide variety of commercial and military applications including in the aerospace, automotive, and energy industries. [9] [16] Early PEM fuel cell applications were focused within the aerospace industry.
It had a PEM fuel cell, a range of 120 miles and a top speed of 70 mph. There were only two seats, as the fuel cell stack and large tanks of hydrogen and oxygen took up the rear portion of the van. Only one was built, as the project was deemed cost-prohibitive. [33] General Electric and others continued working on PEM fuel cells in the 1970s. [30]
Fuel cells are classified by the type of electrolyte they use and by the difference in start-up time ranging from 1 second for proton-exchange membrane fuel cells (PEM fuel cells, or PEMFC) to 10 minutes for solid oxide fuel cells (SOFC). A related technology is flow batteries, in which the fuel can be regenerated by recharging.
Direct methanol fuel cells or DMFCs are a subcategory of proton-exchange membrane fuel cells in which methanol is used as the fuel and a special proton-conducting polymer as the membrane (PEM). Their main advantage is low temperature operation and the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all ...
Ruthenium and platinum are often used together, if carbon monoxide (CO) is a product of the electro-chemical reaction as CO poisons the PEM and impacts the efficiency of the fuel cell. Due to the high cost of these and other similar materials, research is being undertaken to develop catalysts that use lower cost materials as the high costs are ...
Conversely to the PEM fuel cell, the better the PEM electrolyzer the lower the cell voltage at a given current density. The figure below is the result of a simulation from the Forschungszentrum Jülich of a 25 cm 2 single cell PEM electrolyzer under thermoneutral operation depicting the primary sources of voltage loss and their contributions ...