Proton exchange membrane fuel cells application fields

Fuel cells are currently at the early commercial stage for some applications. There are increasing numbers of units deployed in field trials for an increasing number of applicahons. The polymer electrolyte membrane (PEM) fuel cell is one of the most common types of fuel cells under development today. (They also are commonly referred to as proton exchange membrane fuel cells based on the key characteristic of the solid electrolyte membrane to transfer protons from the anode to the cathode.) With the experience gained through... 

The polymer electrolyte membrane fuel cell (PEMFC) also known as proton exchange membrane fuel cell, polymer electrolyte fuel cell (PEFC) and solid polymer fuel cell (SPFC) was first developed by General Electric in the USA in the 1960 s for use by NASA in their initial space applications. The electrolyte is an ion conducting polymer membrane, described in more details in Section 2.2. Anode and cathode are bonded to either side of the membrane. This assembly is normally called membrane electrode assembly (MEA) or EMA which is placed between the two flow field plates (bipolar plates) (Section 2.5) to form what is known as stack . The basic operation of the PEMFC is the same as that of an acid electrolyte cell as the mobile ions in the polymer are or proton. 

Proton exchange membrane fuel cell (PEMFC) is a promising candidate as zero-emission power source for both transportation and stationary applications because of its high efficiency, high power density, low operating temperature, quick startup, etc. Its applications can also be extended to many fields requiring from a few watts to megawatts, such as power supplies in cellular telephone, laptop computers and portable entertainment equipment, and military communication installations [1]. 

Over the last decade, several new proton exchange membranes have been developed. The new polymers in fuel cell applications are based mostly on hydrocarbon structures for the polymer backbone. Poly(styrene sulfonic acid) is a basic material in this field. In practice, poly(styrene sulfonic acid) and the analogous polymers such as phenol sulfonic acid resin and poly(trifluorostyrene sulfonic acid), were frequently used as polymer electrolytes for PEMFCs in the 1960s. Chemically and thermally stable aromatic polymers such as poly(styrene) [ 3 ], poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbony 1-1,4-phenylene) (PEEK) [4], poly(phenylenesulfide) [5], poly(l,4-phenylene) [6, 7], poly (oxy-1,4-phe-nylene) [8], and other aromatic polymers [9-11], can be employed as the polymer backbone for proton conducting polymers. These chemical structures are illustrated in Fig. 6.2. 

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