PEM fuel cell PEMFC

Pelletizing, in pyrometallurgy, 16 140 Pelouze reaction, 17 227 Peltier effect, 21 555 24 428 Pelton wheel turbine, 26 85 Pemanent Red 2B, Strontium Salt, pigment for plastics, 7 366t PEM fuel cell (PEMFC), 12 202-203 PEN, 10 222. See also Poly(ethylene 2,6-naphthalenedicarboxylate) (PEN) Penaeid shrimp, aquacultural chemical needs, 3 209... 

Fuel cells are power generation devices converting chemical energy into electric energy by electrochemical reactions. A typical fuel cell is comprised of two electrodes separated by an electrolyte, with a provision of reactant supply and product removal. Among various types of fuel cells, Ha-O -based polymer electrolyte membrane (PEM) fuel cells (PEMFC) have attracted special attention due to their high efficiency, low temperature operation and suitability for low to medium power generation. Basic components of a PEMFC are PEM, catalyst layer, gas diffusion layer and... 

In PEM fuel cells (PEMFCs), the function of catalyst support layer is to accommodate the catalyst nanoparticles. Nanocomposite such as PEDOT/ carbon nanofiber has proved to be an efficient catalyst support in PEMFCs [40]. 

Material Degradation Prediction In 2002, Franco has invented a multiscale modeling approach (and an associated simulation package originally called MEMEPhys) dedicated to the simulation of PEM fuel cells (PEMFCs) (Fig. 12) but, later, extended for the simulation... 

At a temperature of around 200 °C the fuel cell reaction should proceed much more quickly than it does at the lower temperatures typical for PEM fuel cells (PEMFCs). However, since both H3PO4 and H2P04 can adsorb onto the surface of the Pt catalyst, they significantly lower the reaction kinetics, especially for the oxygen reduction reaction (ORR). Consequently, a PAFC operated at about 200 °C proceeds much more slowly than a PEMFC operated at less than 90 °C. As shown in Figure 11.2, the performance of the state-of-flie-art PAFC operated at 160 °C is about 150 mV lower than that of a PEMFC operated at 70 °C. 

The first PEM (Proton Exchange Membrane) electrolyzers were developed at the same time as the earliest PEM fuel cells (PEMFCs) as part of the US space program GEMINI, run in the 1960s by NASA. 

As one of the core components of the PEM fuel cells (PEMFCs), the PEMs must meet the following requirements to fulfill practical applications (a) chemical and electrochemical stability, (b) high mechanical strength, (c) low permeability to reactant species, (d) high proton conductivity but zero electronic conductivity, and (e) low production cost. Since the chemical structure of SPI membranes has great impact on their performances, it is essential to properly design the molecular structures of the dianhydride and the diamine monomers and to select appropriate polymerization technique. 

While the PEM fuel cells appear to be suitable for mobile applications, SOFC technology appears more applicable for stationary applications. The high operating temperature gives it flexibility towards the type of fuel used, which enables, for example, the use of methane. The heat thus generated can be used to produce additional electricity. Consequently, the efficiency of the SOFC is -60 %, compared with 45 % for PEMFC under optimal conditions. 

Proton Exchange Membrane Fuel Cells (PEMFCs) are being considered as a potential alternative energy conversion device for mobile power applications. Since the electrolyte of a PEM fuel cell can function at low temperatures (typically at 80 °C), PEMFCs are unique from the other commercially viable types of fuel cells. Moreover, the electrolyte membrane and other cell components can be manufactured very thin, allowing for high power production to be achieved within a small volume of space. Thus, the combination of small size and fast start-up makes PEMFCs an excellent candidate for use in mobile power applications, such as laptop computers, cell phones, and automobiles. 

The costs of a PEMFC stack are composed of the costs of the membrane, electrode, bipolar plates, platinum catalysts, peripheral materials and the costs of assembly. For the fuel-cell vehicle, the costs of the electric drive (converter, electric motor, inverter, hydrogen and air pressurisation, control electronics, cooling systems, etc.) and the hydrogen storage system have to be added. Current costs of PEM fuel-cell stacks are around 2000/kW, largely dominated by the costs of the bipolar plates and... 

Proton exchange membranes (PEMs) are a key component in PEM fuel cells (PEMECs) and an area of active research in commercial, government, and academic institutions. In this chapter, the review of PEM materials is divided into two sections. The first will cover the most important properties of a membrane in order for it to perform adequately within a PEMFC. The latter part of this chapter will then provide an overview of existing PEM materials from both academic and industrial research facilities. Wherever possible, the membranes will also be discussed with respect to known structure-property relationships. 

G. Lim and C. Y. Wang. Effects of hydrophobic polymer content in GDL on power performance of a PEM fuel cell. Electrochimica Acta 49 (2004) 4149-4156. G. G. Park, Y. J. Sohn, T. H. Yang, et al. Effect of PTFE contents in the gas diffusion media on the performance of PEMFC. Journal of Power Sources 131 (2004) 182-187. 

Proton exchange membrane fuel cells (PEMFCs) work with a polymer electrolyte in the form of a thin, permeable sheet. The PEMFCs, otherwise known as polymer electrolyte fuel cells (PEFC), are of particular importance for the use in mobile and small/medium-sized stationary applications (Pehnt, 2001). The PEM fuel cells are considered to be the most promising fuel cell for power generation (Kazim, 2000). 

Figure 1.6. PEM fuel cell catalyst layer structure [13]. (Reproduced from Journal of Power Sources, 102, Costamagna P, Srinivasan S, Quantum jumps in the PEMFC science and technology from the 1960s to the year 2000 Part II. Engineering, technology development and application aspects, 253-69 2001, with permission from Elsevier.)...

Figure 3.13. Typical polarization curve for a PEMFC [14]. (Modified from Barbir F. PEM fuel cells theory and practice. New York Elsevier Academic Press, 2005, with permission from Elsevier.)...

Figure 6.54. Performance of a PBI-based PEMFC at different operating temperatures [45], (Reprinted from Journal of Power Sources, 172(1), Zhang J, Tang Y, Song C, Zhang J, Poly benzimidazole-membrane-based PEM fuel cell in the temperature range of 120-200°C, 163-71, 2007, with permission from Elsevier.)...

PEM fuel cells use a solid proton-conducting polymer as the electrolyte at 50-125 °C. The cathode catalysts are based on Pt alone, but because of the required tolerance to CO a combination of Pt and Ru is preferred for the anode [8]. For low-temperature (80 °C) polymer membrane fuel cells (PEMFC) colloidal Pt/Ru catalysts are currently under broad investigation. These have also been proposed for use in the direct methanol fuel cells (DMFC) or in PEMFC, which are fed with CO-contaminated hydrogen produced in on-board methanol reformers. The ultimate dispersion state of the metals is essential for CO-tolerant PEMFC, and truly alloyed Pt/Ru colloid particles of less than 2-nm size seem to fulfill these requirements [4a,b,d,8a,c,66j. Alternatively, bimetallic Pt/Ru PEM catalysts have been developed for the same purpose, where nonalloyed Pt nanoparticles <2nm and Ru particles <1 nm are dispersed on the carbon support [8c]. From the results it can be concluded that a Pt/Ru interface is essential for the CO tolerance of the catalyst regardless of whether the precious metals are alloyed. For the manufacture of DMFC catalysts, in... 

---