Proton exchange electrolyte fuel cell

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. 

Membrane-type fuel cells. The electrolyte is a polymeric ion-exchange membrane the working temperatures are 60 to 100°C. Such systems were first used in Gemini spaceships. These fuel cells subsequently saw a rather broad development and are known as (solid) polymer electrolyte or proton-exchange membrane fuel cells (PEMFCs). 

Ambient temperature catalysis of O2 reduction at low overpotentials is a challenge in development of conventional proton exchange membrane fuel cells (pol5mer electrolyte membrane fuel cells, PEMFCs) [Ralph and Hogarth, 2002]. In this chapter, we discuss two classes of enz5mes that catalyze the complete reduction of O2 to H2O multi-copper oxidases and heme iron-containing quinol oxidases. 

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. 

This survey focuses on recent developments in catalysts for phosphoric acid fuel cells (PAFC), proton-exchange membrane fuel cells (PEMFC), and the direct methanol fuel cell (DMFC). In PAFC, operating at 160-220°C, orthophosphoric acid is used as the electrolyte, the anode catalyst is Pt and the cathode can be a bimetallic system like Pt/Cr/Co. For this purpose, a bimetallic colloidal precursor of the composition Pt50Co30Cr20 (size 3.8 nm) was prepared by the co-reduction of the corresponding metal salts [184-186], From XRD analysis, the bimetallic particles were found alloyed in an ordered fct-structure. The elecbocatalytic performance in a standard half-cell was compared with an industrial standard catalyst (bimetallic crystallites of 5.7 nm size) manufactured by co-precipitation and subsequent annealing to 900°C. The advantage of the bimetallic colloid catalysts lies in its improved durability, which is essential for PAFC applicabons. After 22 h it was found that the potential had decayed by less than 10 mV [187],... 

PEM Proton-exchange-membrane fuel cell (Polymer-electrolyte-membrane fuel cell) Proton- conducting polymer membrane (e.g., Nafion ) H+ (proton) 50-80 mW (Laptop) 50 kW (Ballard) modular up to 200 kW 25-=45% Immediate Road vehicles, stationary electricity generation, heat and electricity co-generation, submarines, space travel... 

PAFC PEMFC PFC PGM PHEV PISI PM POX ppm PPP Phosphoric-acid fuel cell Proton-exchange-membrane fuel cell Polymer-electrolyte membrane Perfluorocarbons Platinum-group metals Plug-in hybrid-electric vehicle Port-injection spark ignition Particulate matter Partial oxidation Parts per million Purchasing power parity... 

The PEMFC (Proton Exchange Membrane Fuel Cell) is a fuel cell with a protonconducting fluorinated polymer as electrolyte. Figure 14.12 gives a schematic drawing of the PEMFC. At the anode, hydrogen is oxidized to protons. At the cathode, oxygen from air is reduced to water. The PEMFC is in development for various applications. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

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 29. Conductivity of some intermediate-temperature proton conductors, compared to the conductivity of Nafion and the oxide ion conductivity of YSZ (yttria-stabilized zirconia), the standard electrolyte materials for low- and high-temperature fuel cells, proton exchange membrane fuel cells (PEMFCs), and solid oxide fuel cells (SOFCs).

Proton exchange membrane fuel cell (PEMFC) working at around 70 °C with a polymer membrane electrolyte, such as Nafion, which is a solid proton conductor (conducting by the H + cation). 

According to the electrolyte and working temperature, one distinguishes the low-temperature fuel cell technologies (i) alkaline fuel cell, AFC (70 to 80°C), (ii) proton exchange membrane fuel cell, PEMFC (70 to 80°C), (iii) phosphoric acid cell, PAFC (200°C) from the high-temperature technologies, (iv) molten carbonate fuel cell, MCFC (650 to 700°C), and (v) solid oxide fuel cell, SOFC (1000°C). 

Acid polymer membrane or Polymer Electrolyte Membrane or Proton Exchange Membrane fuel cells (also known as PEMFC)... 

Note PAFC phosphoric acid fuel cell PEMFC proton exchange membrane fuel cell/polymer electrolyte membrane fuel cell MBFC microbiological fuel cell DMFC direct methanol conversion fuel cell AFC alkaline fuel cell MCFC molten carbonate fuel cell SOFC solid oxide fuel cell ZAFC zinc air fuel cell. 

Smith B, Sridhar S, Khan A, (2005). Solid polymer electrolyte membranes for fuel cell applications-a review. Journal of Membrane Science 259 10-26 Sopian K, Wan Daud W, (2006). Challenges and future developments in proton exchange membrane fuel cells. Renewable Energy 31 719-727 Srinivasan S, (2006). Fuel cells From fundamentals to applications. Springer Science and Business Media LLC, New York... 

Proton exchange membrane fuel cell - polymer-electrolyte-membrane fuel cell (PEMFC)... 

An electrolyte is an essential component within fuel cells, used to facilitate the selective migration of ions between the electrodes. Fuel cells are typically classified according to the electrolytes used alkaline fuel cell (AFC), polymer electrolyte (or proton exchange membrane) fuel cell (PEMFC), phosphoric acid fuel cell (PAFC),... 

Malhotra, S. Datta, R., Membrane-Supported Nonvolatile Acidic Electrolytes Allow Higher Temperature Operation of Proton-Exchange Membrane Fuel Cells. Journal of The Electrochemical Society 1997, 144, (2), L23-L26. 

This survey focuses on recent catalyst developments in phosphoric acid fuel cells (PAFC), proton exchange membrane fuel cells (PEMFC), and the previously mentioned direct methanol fuel cell (DMFC). A PAFC operating at 160-220 °C uses orthophosphoric acid as the electrolyte the anode catalyst is Pt and the cathode can... 

The combination of anode/electrolyte/cathode in proton exchange membrane fuel cell is usually referred to as the membrane electrode assembly (MEA).51 Usually the MEA was produced by attaching a catalyst layer (frequently Pt, Pt alloys, or other noble metals) on one side of porous gas diffusion electrodes. The catalysts... 

Malhotra, S. Datta, R. Membrane-supported nonvolatile acidic electrolytes allow higher temperature operation of proton-exchange membrane fuel cells. J. Electrochem. Soc. 1997,144, L23. 

In proton exchange membrane fuel cells, perhaps the most divulgate type of fuel cells, a proton-conducting polymer membrane acts as the electrolyte separating the anode and cathode sides. Porous anaodic alumina (Bocchetta et al., 2007) and mesoporous anastase ceramic membranes have been recently introduced in this field (Mioc et al., 1997 Colomer and Anderson, 2001 Colomer, 2006). 

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