Temperature NAFION Based PEMFC

As a base of proton conducting membrane polyvinyl alcohol (PVS) and phenolsulfonic acid (PSA) was synthesized [9]. Membrane is rendered on a surface of a catalytic layer and dries up at room temperature. As shown in [9], at ratio PVS PSA=4 1 the membrane surpasses widely used in PEMFC membranes on the Nafion basis. Besides, experimental data testily that the solution can successfully be used as a connecting element for the anode and the cathode bonding at FC assembly. 

PEMFCs generally operate at temperatures <100°C. PFSA-based polymer ionomer membranes like Nafion, Gore, Aciplex, and Flemion are not significantly affected by temperatures up to 150°C where most of the water is lost and membranes may suffer irreversible dry out. Chemical degradation of these membranes in the form usually starts with the loss of sulfonate groups at over 220°C [7]. 

Over the past decade, proton exchange membranes for fuel cells (PEMFCs) have undergone significant development. It has been demonstrated that the overall system size can be reduced and carbon monoxide tolerance can be increased by operating the fuel cell stack at much higher temperatures than 1(X) °C and even as high as 180 °C. However, the loss of water from a Nafion-type membrane at higher temperatures (>100 °C) results in a rapid loss of conductivity [92,93]. Thus, the development of a suitable alternate water-based proton... 

Many different types of fuel-cell membranes are currently in use in, e.g., solid-oxide fuel cells (SOFCs), molten-carbonate fuel cells (MCFCs), alkaline fuel eells (AFCs), phosphoric-acid fuel cells (PAFCs), and polymer-electrolyte membrane fuel cells (PEMFCs). One of the most widely used polymers in PEMFCs is Nalion, which is basically a fluorinated teflon-like hydrophobic polymer backbone with sulfonated hydrophilic side chains." Nafion and related sulfonic-add based polymers have the disadvantage that the polymer-conductivity is based on the presence of water and, thus, the operating temperature is limited to a temperature range of 80-100 °C. This constraint makes the water (and temperature) management of the fuel cell critical for its performance. Many computational studies and reviews have recently been pubhshed," and new types of polymers are proposed at any time, e.g. sulfonated aromatic polyarylenes," to meet these drawbacks. 

To increase the membrane s operational temperature to 130°C, Matos et al. (2011) prepared Nafion/titania-based filler composites by casting. Three types of titania-based fillers were investiated (1) nanoparticles with nearly spherical shape, (2) mesoporous particles with a high surface area, and (3) hydrogen titanate nanotubes. The addition of titanate nanotubes changed the physical properties of the composites more markedly than did its addition to the other versions. Polarization measurements showed that composite electrolytes boost PEMFC performance significantly at 130°C. 

Proton-exchange membrane fuel cells (PEMFC)—use solid-polymer proton-conducting membrane electrolyte at temperatures generally ranging from ambient to 90°C. Today s technology primarily uses the trifluoromethanesulfonic-acid-based electrolyte membrane, such as DuPont s Nafion . 

The fuel cells are classified based on the fuel, operating temperature, electrolyte type, physical state of fuel cell components and the fabrication technology. The polymer electrolyte membrane fuel cell (PEMFC) operating on a methanol-water mixture as a fuel is called a Direct Methanol Fuel Cell (DMFC). DMFC uses sulphonated fluoropolymer, such as NAFION 117 as the electrolyte membrane. Nafion membranes require high levels of humidification and can operate comfortably only within a narrow temperature range of 25°C... 

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