Automotive polymer electrolyte membrane

Wieser, C. 2004. Novel polymer electrolyte membranes for automotive applications—Requirements and benefits. Fuel Cells 4 245-250. 

In the past two decades, fuel cells and in particular imi-exchange membranes have become a top priority topic in material research. Fuel cells are seen as promising alternative energy conversion systems replacing the combustion-based techniques. Among the various types of fuel cells, the low-temperature fuel cells like the polymer electrolyte membrane fuel cell (PEMFQ, DMFC, or alkaline fuel cell (AFC) are the most flexible ones concerning range of appUcations e.g. portable, automotive, and stationary. 

The best catalysts for the electrochemical oxidation and production of hydrogen are platinum metal and the hydrogenase enzymes. Both catalyze the reaction of two protons with two electrons to form H2, as shown in Equation 7.1. Because of its superior catalytic rates and overpotentials compared to other metals and because of its high stabihty compared to hydrogenase enzymes, platinum is currently used as the catalyst for both half reactions (the oxidation of H2 and the reduction of O2) in polymer electrolyte membrane (PEM) fuel cells, which have been proposed for automotive transportation [1]. However, the high cost of platinum provides a strong impetus for developing less expensive alternatives. 

The proton exchange membrane - also known as polymer electrolyte membrane (PEM) - fuel cell uses a polymeric electrolyte. The protonconducting polymer forms the heart of each cell electrodes, usually made of porous carbon with catalytic platinum incorporated into them, are bonded to either side of the electrolyte to form a one-piece membrane-electrode assembly (MEA). The following are some key advantages that make PEMs such a promising technology for the automotive market ... 

M. Mathias, H. Giasteiger, R. Makharia, S. Kocha, T. T. Xie, and J. Pisco, Can Available Membranes and Catalysts Meet Automotive Polymer Electrolyte Fuel Cell Requirements, 228th National Meeting of the ACS Meeting, Philadelphia, August (2004). 

For automotive application only PEMs (Polymer Electrolyte Membrane or Proton Exchange Membrane) are used. There are two main advantages by using this technology the cold start capabilities and the power density. If several single cells are stacked together and cormected in series you get a fuel cell stack as depicted in Eig. 4.22. 

Polymer Electrolyte Membrane (PEM) Fuel Cells, Automotive Applications... 

Automotive applications of polymer electrolyte membrane fuel cells require intermediate temperature operation at pressures below... 

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