DuPont fuel cells

One activity at DuPont Fuel Cells business center is the development of a thinner membrane with sufficient mechanical stability. Thinner membranes translate into higher current density, which in turn means a higher electrical efficiency. The trade-off is a less mechanically robust membrane. Nafion membranes are nonreinforced films based on Nafion resin, a PFS A/PTFE copolymer in the acid (H+) form. DuPont is especially marketing Nafion PFSA NR-111 and NR-112 membranes as nonreinforced dispersion-cast films for that purpose. These membranes are delivered as a composite with the membrane positioned between a backing film and a coversheet. This composite is wound on a 6 in. ID plastic core, with the backing film facing out, as shown in Figure 21.19. 

Description. Incorporated in September 2001, Fuel Cells Texas is a non-profit trade association representing the fuel cell industry in Texas. The mission of Fuel Cells Texas is to "accelerate the broad commercialization and deployment of fuel cells in the state of Texas through public education, policy alignment, and development of state-sponsored initiatives." The members of Fuel Cells Texas include FuelCell Energy, Hunt Power, Methanex Corporation, Siemens Westinghouse Power Corporation, DuPont Fuel Cells, IdaTech, Plug Power,... 

The current state-of-the-art proton exchange membrane is Nafion, a DuPont product that was developed in the late 1960s primarily as a permselective separator in chlor-alkali electrolyzers. Nation s poly(perfluorosulfonic acid) structure imparts exceptional oxidative and chemical stability, which is also important in fuel cell applications. 

Sulfonated EPDMs are formulated to form a number of rubbery products including adhesives for footwear, garden hoses, and in the formation of calendered sheets. Perfluori-nated ionomers marketed as Nation (DuPont) are used for membrane applications including chemical-processing separations, spent-acid regeneration, electrochemical fuel cells, ion-selective separations, electrodialysis, and in the production of chlorine. It is also employed as a solid -state catalyst in chemical synthesis and processing. lonomers are also used in blends with other polymers. 

Proton exchange membrane (pem) fuel cells, also known as polymer electrolyte membrane fuel cells, have a plastic electrolyte. The membrane material most widely used in pems is produced by DuPont and looks like the plastic wrap used for storing foods. The word proton refers to the hydrogen ion that passes through the polymer membrane. 

The proton exchange membranes (PEMs) used in PEM fuel cells consist of two domains the hydrophobic polymer backbone domain and the hydrophilic ionic cluster domain. The most commonly used membrane is Nafion , produced by DuPont. 

The ionic resistance of a polymer electrolyte membrane is an important parameter in determining the mobility of protons through the membrane and the corresponding voltage loss across the membrane. Currently, the most commonly used membranes in PEM fuel cells are Nafion membranes produced by DuPont. However, these membranes are limited to low-temperature uses (usually below 80°C) because membrane dehydration at high temperatures can lead to reduced water content and then a lower proton transfer rate, resulting in a significant decrease in conductivity. The relationship between conductivity and the diffusion coefficient of protons can be expressed by the Nemst-Einstein equation ... 

DuPont is already heavily invested in products, services, and research in support of global energy markets as diverse as petrochemicals, fuel cells, photovoltaics, and biofuels. The company supplies products to the sugar- and corn-based... 

The idea of using an ion-conductive polymeric membrane as a gas-electron barrier in a fuel cell was first conceived by William T. Grubb, Jr. (General Electric Company) in 1955. - In his classic patent, Grubb described the use of Amber-plex C-1, a cation exchange polymer membrane from Rohm and Haas, to build a prototype H2-air PEM fuel cell (known in those days as a solid-polymer electrolyte fuel cell). Today, the most widely used membrane electrolyte is DuPont s Nation... 

Perfluorinated membranes are still regarded as the best in the class for PEM fuel cell applications. - These materials are commercially available in various forms from companies such as DuPont, Asahi Glass, Asahi Chemical, 3M, Gore, and Sol-vay. Perfluorosulfonic acid (PFSA) polymers all consist of a perfluorocarbon backbone that has side chains terminated with sulfonated groups. 

Ashok Dhingra, Dupont What part of your new concept car in 2000 will involve materials innovation and what will involve the innovation in energy such as fuel cells and other competing technologies ... 

Nafion, a perfluorinated sulfonic acid (PFSA) polymer electrolyte developed and produced by the E. I. Dupont Company, has been extensively studied as a fuel cell membrane. Despite its age, it remains the industry standard membrane because of its relatively high proton conductivity, toughness and quick start capabilities. Attempts to build upon the strengths of Nafion have resulted in a class of PFSA polymer electrolytes, including the short-side-chain (SSC) PFSA polymer electrolyte, originally synthesized by Dow and now produced by Solvay Solexis. Stracturally, PFSA polymer... 

Subsequent to these early developments of alloy electrocatalysts in the PAFC technology, have been attempts to use the same in pefluorinated sulfonic acid fuel cells (solid state membranes such as Nation from Dupont, Dow, Asahi and others). Yeagei has reviewed the effect of different electrolytes on the ORR electrocatalysis. The summaiy of this work was that the solid state peifluorinated acid environment offered a significant advantage over phosphoric acid. These were... 

The membrane and ionomer humidification requirements are of paramount importance for PEMFC operation since the proton conductivity is a fundamental necessity in the membrane as well as in the electrode for the fuel cell to function. The operating conditions of current PEMFCs are dictated by the properties of the membranes/ionomers. Now, the most important membrane type (e.g., Nafion membranes from DuPont) is based on PFSA ionomers that are used in the membrane... 

In the development of fuel-cell technology based on this unique polymer electrolyte, special chapters in electrochemical science and engineering have emerged, addressing the fuel-cell ionomeric membrane itself and the optimized fabrication of MEAs. The invention of Nafion, a poly(perfluorosulfonic acid) (poly(PFSA)) at DuPont in the 1960s, was, in fact, a key (if not the key) milestone in the development of PEFC technology. The chemical and mechanical properties of such poly(PFSA) extruded membranes, which are based on a perfluorocar-bon backbone, enabled to achieve stable materials properties and, consequently,... 

Perfluorinated ionomers have reached a high level of industrial importance due to their outstanding performance as membranes in applications such as chior-alkali cells and fuel cells (1). The Nafion material synthesized by duPont more than twenty years ago... 

The most diffused material for membranes is based on co-polymers of tetrafluoroethylene (TEE) with perfluorosulfonate monomers. The resulting co-polymer is constituted by polytetrafluoroethylene polymeric chain (PTFE, commercially known as Teflon) in which some fluorine atoms are substituted by sulfonated side chains. The monomer perfluoro-sulfonyfluoride ethyl-propyl-vinyl ether is used in membranes commercialized by Dupont with the registered trademark Nafion (Fig. 3.2), which is the most well-known material used as electrolyte in PEM fuel cells. 

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