Polymer electrolyte membrane Nafion

In the 1960s, the use of solid-state polymer electrolytes instead of the liquid electrolytes normally used in alkaline electrolysis led to the development of novel concepts for water electrolysis. The US company General Electric was the first to realize solid polymer electrolyte water electrolysis (SPE) with the aid of the solid polymer electrolyte membrane (Nafion ) developed by DuPont [16]. At the same time, ABB [17, 18] in Switzerland and Fuji Electric [19] in Japan also developed PEM electrolyzers with single electrode areas of up to 2500 cm. These... 

State-of-the-Art Commercial Polymer Electrolyte Membrane (Nafion).412... 

STATE-OF-THE-ART COMMERCIAL POLYMER ELECTROLYTE MEMBRANE (NAFION)... 

Consider the polymer electrolyte membrane, Nafion-117 (PEM) fuel cell operating at a temperature of 80°C with the following known data ... 

Choe, Y. K., Tsnchida, E., Dteshoji, T., Yamakawa, S., Hyodo, S., Nature of proton dynamics in a polymer electrolyte membrane, nafion A first-principles molecnlar dynamics study. PCCP 2009,11 (20), 3892-3899. 

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... 

Hietala, S., Maunu, S. L. and Sundholm, E. 2000. Sorption and diffusion of methanol and water in PVDE-y-PSSA and Nafion 117 polymer electrolyte membranes. Journal of Polymer Science Part B Polymer Physics 38 3277-3284. 

Bauer, F., Denneler, S. and Wilert-Porada, M. 2005. Influence of temperature and humidity on the mechanical properties of Nafion 117 polymer electrolyte membrane. Journal of Polymer Science Part B Polymer Physics 43 786-795. 

Schematic depiction of the structural evolution of polymer electrolyte membranes. The primary chemical structure of the Nafion-type ionomer on the left with hydrophobic backbone, side chains, and acid head groups evolves into polymeric aggregates with complex interfacial structure (middle). Randomly interconnected phases of these aggregates and water-filled voids between them form the heterogeneous membrane morphology at the macroscopic scale (right).

Polymer electrolyte membrane fuel cell (PEMFC) 80-90 Polymer membrane (Nafion) Hydrogen, reformed methanol or methane 50-60 Transport, electro car, space flight, shipping... 

In a H2/air fuel cell, the protons produced at the anode side need to be transferred to the cathode side to react with 02. This requires a proton transport electrolyte. Nafion membranes, composed of a perfluorosulfonated polymer, are the most commonly used polymer electrolyte membranes to conduct protons. The structure of the Nafion membrane is shown in Figure 1.5. Nafion can take on a... 

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 ... 

Among the proton-conducting membranes Nation or Nafion-like sulfonated perfluorinated polymers should also be mentioned. These materials are used for polymer electrolyte membrane (PEM) fuel cells, and in addition to being chemically very stable, they exhibit high proton conductivity at temperatures lower than 100°C. It is believed that permeability and thermal stability may be increased if tailor-made lamellar nanoparticles are added to a proton conducting polymer. 

The Nafion 117 (Du Pont, USA) was used as a polymer electrolyte membrane. The membrane was pretreated by boiling in 3 wt.% H2O2 solution for 1 h, followed by boiling in 0.5 M H2SO4 for Ih. Thereafter, the membrane was placed in boiling water for 1 h, and the procedure was repeated at least twice to remove completely the sulfuric acid. 

K.M. Nouel and PS. Fedkiw, Nafion based composite polymer electrolyte membrane, Electrochim. Acta, 1998, 43, 2381-2387. 

L.J. Hobson, H. Ozu, M. Yamaguchi and S. Hayase, Modified Nafion 117 as an improved polymer electrolyte membrane for direct methanol fuel cell, J. Electrochem. Soc., 2001, 148, A1185-A1190. 

M. Watanabe, H. Uchida and M. Emori, Polymer electrolyte membranes incorporated with nanometer-size particles of Pt and/or metal-oxides Experimental analysis of the self-humification and suppression of gas-crossover in fuel cell, J. Phys. Chem., B, 1998, 102, 3129-3137 M. Watanabe, H. Uchida, Y. Seki and M. Emori and P. Stonehart, Self-humidifying polymer electrolyte membranes for fuel cell, J. Electrochem. Soc., 1996, 143, 3847-3852 H. Uchida, Y. Mizuno and M. Watanabe, Suppression of methanol crossover in Pt-dispersed polymer electrolyte membrane for direct methanol fuel cell, Chem. Lett., 2000, 1268-1269 H. Uchida, Y. Ueno, H. Hagihara and M. Watanabe, Self-humidifying electrolyte membranes for fuel cells, preparation of highly dispersed Ti02 particles in Nafion 112, J. Electrochem. Soc., 2003, 150, A57-A62. 

While Nafion , a perfluorinated polymer developed by DuPont, is the most commonly used proton conductive polymer electrolyte membrane it is an insufficient solution in a number of areas. It has high cationic transport (approximately 9.56 5/cm) [8] but also has high levels of methanol fuel crossover, slow anode kinetics and very high cost [12]. Fuel cell membrane performance can be estimated from the ratio of proton conductivity (a) to methanol permeability (P). The higher the value of a/P, the better the membrane performance would be [13]. Chitosan has been shown to have a much lower methanol permeability than Nafion [14], and as such, a great deal of attention focused on developing chitosan membranes with high levels of ionic conduction and low methanol permeability as delineated in Table 3.1. 

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