Proton exchange membrane density

Proton Exchange Membrane 0-85 Can operate at ambient temperature High power density Sensitive to CO-poisoning Need for humidification Transportation Distributed Power... 

The most promising fuel cell for transportation purposes was initially developed in the 1960s and is called the proton-exchange membrane fuel cell (PEMFC). Compared with the PAFC, it has much greater power density state-of-the-art PEMFC stacks can produce in excess of 1 kWA. It is also potentially less expensive and, because it uses a thin solid polymer electrolyte sheet, it has relatively few sealing and corrosion issues and no problems associated tvith electrolyte dilution by the product water. 

J. Srmivason, et al., "High Energy Efficiency and High Power Density Proton Exchange Membrane Fuel Cells - Electrode Kinetics and Mass Transport," Journal of Power Sources, p. 36, 1991. 

Murphy, O. J., Hitchens, G. D., and Manko, D. J. High-power density proton-exchange membrane fuel cells. Journal of Power Sources 1994 47 353-368. 

The use of chlorine in a fuel cell system for space power applications has been suggested [100]. The CI2/H2 system is based on a proton-exchange membrane fuel cell design and is shown to give superior power and energy density when compared to conventional systems. 

P P Po PCHE PCR PCS PDF PDMS Pe PEM PEMFC PET pH Power output Pressure Pressure drop of one SAR step Printed circuit heat-exchanger Printed circuit reactor Process control system Probability density function Poly-dimethylsiloxane Peclet-number Proton exchange membrane Proton exchange membrane fuel cell Poly-ethylene terephthalate Potentia Hydrogenii (measure for acid and base strength)... 

In proton exchange membrane (PEM) or solid polymer electrolyte (SPE) electrolysis, the electrolyte is replaced by an ion-exchange resin. These units are compact, provide high current densities, but are more expensive, and because of the corrosive nature of the electrolyte, require special construction materials. 

General. There is no doubt that a comparison (updated in the 1990s) of the potential vs. current density plot for the various fuel cells (see Fig. 13.27) shows that the proton exchange membrane fuel cell with a perfluoropolymer sulfuric acid has superior performance (i.e., higher cell potential and hence efficiency) compared with the other types of fuel cells. Because this cell has been chosen for development by the majority of the automotive manufacturers, special attention is given here to its development. 

Fig. 13.27. Potential vs. current density plots for state-of-the-art fuel cells, o, proton exchange membrane fuel cell , solid oxide fuel cell , pressurized phosphonic acid fuel cell (PAFC) a, direct methanol fuel cell, direct methanol PAFC , alkaline fuel cell. (Reprinted from M. A. Parthasarathy, S. Srinivasan, and A. J. Appleby, Electrode Kinetics of Oxygen Reduction at Carbon-Supported and Un-supported Platinum Microcrystal-lite/Nafion Interfaces, J. Electroanalytical Chem. 339 101-121, copyright 1992, p. 103, Fig. 1, with permission from Elsevier Science.)...

Proton exchange membranes, whether operating in electrolysis mode or fuel cell mode, have the property of higher efficiency at lower current density. There is a 1 1 relationship in electrolysis between the rate of hydrogen production and current applied to the system. 

Nafion 117 membranes were electroless coated with Pt from a solution ofH2PtCl6 and hydrazine (N2H4) as reducing agent.58 The coated membrane was used to make an MEA of proton exchange membrane fuel cell which was tested at 60°C in a saturated H2/O2 system. The maximum current density of about 80 mA/cm2 at 0.3 V was obtained in this system. 

The PE MFC has a solid ionomer membrane as the electrolyte, and a platinum, carbon-supported Pt or Pt-based alloy as the electrocatalyst. Within the cell, the fuel is oxidized at the anode and the oxidant reduced at the cathode. As the solid proton-exchange membrane (PEM) functions as both the cell electrolyte and separator, and the cell operates at a relatively low temperature, issues such as sealing, assembly, and handling are less complex than with other fuel cells. The P EM FC has also a number of other advantages, such as a high power density, a rapid low-temperature start-up, and zero emission. With highly promising prospects in both civil and military applications, PEMFCs represent an ideal future altemative power source for electric vehicles and submarines [6]. 

Proton exchange membrane (PEM) fuel cells are the best choice for automobiles due to their high-power density, low mass, and low operating temperatures as compared to other types of fuel cells. 

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