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The Poylmer Electrolyte Membrane Fuel Cell

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A fuel cell is mainly used to provide electricity from chemical reactions. It harnesses the chemical energy of hydrogen and oxygen to generate electricity without combustion one of the basic types of fuel cells is the Polymer Electrolyte Membrane Fuel Cell (PEMFC). This section will give a general description of its parts, how do they function and the material they are consisted of. 3.2 Background Polymer electrolyte membrane fuel cells operate at relatively low temperatures, around 80°C (176°F). Low-temperature operation allows them to start fast (less warm-up time) and results in less wear on system components, which result in better durability. However, it requires that a noble-metal catalyst (typically platinum) be used to separate the hydrogen's electrons and protons, adding cost to the system. PEM fuel cells are used primarily for transportation applications and some stationary applications. Due to their fast startup time, low sensitivity to orientation, and favorable power-to-weight ratio, PEM fuel cells are particularly suitable for use in passenger vehicles, such as cars and buses. A significant barrier to using these fuel cells in vehicles is hydrogen storage. Most fuel cell vehicles (FCVs) powered by pure hydrogen must store the hydrogen on-board as a compressed gas in tanks. Due to the low-energy density of hydrogen, it is difficult to store enough hydrogen on-board to allow vehicles to travel the same distance as gasoline-powered vehicles before refueling. This increases costs and maintenance. They deliver high-power density and offer the advantages of low weight and volume, compared with other fuel cells. 3.3 PEMFC structure Figure PEMFC- 1 Polymer ... ... middle of paper ... ...for the fuel cell. [Lister & McLean ] • Electrolyte membrane: The electrolyte membrane is usually made of Nafion because its availability, low cost, low permeability, good chemical stability and strength. However, it is expensive. [Lister & McLean ] • Catalyst: The most widely used catalyst for PEM fuel cells is Platinum. Platinum catalyst layers are rough and porous to give larger surface area for Oxygen and Hydrogen to react with Pt. They can be as particles as well. [Wang 2011] • Current collectors, GDL and bipolar plates: Current collectors are made of graphitic materials due to its good conduction. GDL gas diffusion layers are made of carbon paper, which has low electronic resistance in order to provide maximum electronic contact and prevent water flooding. Bipolar plates are made of either graphite sot thermosets materials. [Lister & McLean ]
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