SPE fuel cells

The cell design is similar to that of fuel cells . SPE electrolysers are commercially available for small scale, oxygen generators used in space craft and submarines and also for large scale hydrogen production using off-peak electricity. 

S. Tsushima, K. Teranishi, S. lErai, Water diffusion measurement in fuel-cell SPE membrane by NMR, Energy 30 (2005) 235—245. 

Fig. 11. Solid polymer electrolyte (SPE) fuel cell (a) cell design and (b) power curve at 25°C.

Fuel cells (hydrogen-oxygen, hydrogen-air, methanol-air) and industrial electrolysis (water, chlor-alkali) using ion-exchange membranes are the most demanding applications for the membranes. In these apphcations, the membranes have often been designated as SPE, which can be read as solid polymer electrolyte or solid... 

Solid oxide fuel cell(s) (SOFCs), 12 201, 204, 205, 223-227, 13 845, 860-861 Solid-phase epitaxy, 14 447 Solid phase extraction (SPE)... 

SCO SCPC SD SEC SMR SNG SOFC SPE SRES SULEV SUV Synthetic crude oil Super-critical pulverised coal System dynamics US Securities and Exchange Commission Steam methane reformer Synthetic natural gas Solid-oxide fuel cell Society of Petroleum Engineers IPCC Special Report on Emissions Scenarios Super-ultra-low-emission vehicle Sport utility vehicle... 

Lawrence, R. J., and Wood, L. D. Method of making solid polymer electrolyte catalytic electrodes and electrode made thereby. U.S. Patent 4,272,353,1981. Fedkiw, P. S., and Her, W. H. An impregnation-reduction method to prepare electrodes on Naifon SPE. Journal of the Electrochemical Society 1989 136 899-900. Aldebert, P, Novel-Cattin, R, Pineri, M., Millet, P, Doumain, G., and Durand, R. Preparation and characterization of SPE composites for electrolyzers and fuel cells. Solid State Ionics 1989 35 3-9. 

Ion-exchanger resins as solid polymer electrolytes, impregnated with the cations of the chosen anode metal, may prove applicable. Their use in the fuel-cell/electrolyzer single module concept is already under investigation as to complexity and operability (115). Doubtless better SPE s will be discovered. 

With the SPE configuration, electrodes are pressed against the membrane so that the thickness of the latter fixes the interelectrode gap. A membrane can be thiimer than a physical separator, thus reducing such a kind of contribution to IR. The ensemble of electrode and membrane is usually referred to as a membrane-electrode assembly (MEA). This term is used irrespective of the operation of the cell, that is, for both electrolyzers and fuel cells. 

Electrochemical gas detection instruments have been developed which use a hydrated solid polymer electrolyte sensor cell to measure the concentration of specific gases, such as CO, in ambient air. These instruments are a spin-off of GE aerospace fuel cell technology. Since no liquid electrolyte is used, time-related problems associated with liquid electrolytes such as corrosion or containment are avoided. This paper describes the technical characteristics of the hydrated SPE cell as well as recent developments made to further improve the performance and extend the scope of applications. These recent advances include development of NO and NO2 sensor cells, and cells in which the air sample is transported by diffusion rather than a pump mechanism. 

A somewhat different type of rechargeable Li cell is being developed by workers who intend to use a solid polymer membrane as separator [see the use of solid polymer electrolyte (SPE) membranes in some fuel cells (Section 13.6.6)]. The advantage here... 

Solid Polymer Electrolyte (SPE) Fuel Cells McElrov, J. Status of Solid Electrolyte Fuel Cell Technology. National Fuel Cell Seminar Abstracts, San Francisco, California, July 11-13, 1978, pp. 176-179. 

The fundamental principle of SPE reactors is the coupling of the transport of electrical charges, i.e. an electrical current with a transport of ions (cations or anions), through a SPE membrane due to an externally applied (e.g. electrolysis) or internally generated (e.g. fuel cells) electrical potential gradient. For example, in a chlorine/alkaline SPE reactor (Fig. 13.3), the anode and cathode were separated by a cation-SPE membrane (e.g. Nafion 117) forming two compartments, containing the anolyte (e.g. 25 wt% NaCl solution) and the catholyte (e.g. dilute sodium hydroxide), respectively. 

In a fuel cell, chemical energy is converted into electrical energy. For instance, in an H2-02 fuel cell (Fig. 13.4), porous electrodes and catalyst layers are separated by a SPE membrane (e.g. Nation 117). 

A porous anode and cathode are attached to each surface of the membrane, forming a membrane-electrode assembly, similar to that employed in SPE fuel cells. Electrochemical reactions (electron transfer-l-hydrogenation) occur at the interfaces between the ion exchange membrane and electrochemically active layers of electrodes. Electrochemical reductive HDH occurred at the interfaces between the ion exchange membrane and the cathode catalyst layer when an electrical current is applied between the electrodes ... 

Ktxver A, Vogel I, Vielstich W (1994) Distinct performance evaluation of a direct methanol SPE fuel cell. A new method using a dynamic hydrogen reference electrode. 

Although the SPE fuel cell can be considered to be a technological success, it could not be introduced into everyday commercial use because of its liigh cost, wliich is due mainly to the high cost of the ion-selective polymer membrane and the heavy loading of the noble metal catalysis needed for satisfactory operation. 

The solid polymer electrolyte (SPE) fuel cell makes use of the high stability and the cation selectivity of Nafion, a Teflon-like material that has been modified by the incorporation of sulfonic groups. The membrane is coaled with a porous catalyst on both sides. Hydrogen is oxidized on one side of the membrane and the formed in the process is transported across the membrane to the other side, where it interacts with (OH) ions formed by the reduction of oxygen, to form water. This water is removed from the cell by capillary action with the use of a... 

Synthesis of pure hydrogen peroxide using solid polymer electrolytes (SPE) could eliminate the need to separate the product from liquid electrolytes (basic or acidic). Designs of the (SPE) fuel cell type of reactor could be investigated for such a process. Tatapudi and Fenton [71, 80] demonstrated the basic feasibility of this process (with or without concurrent anodic ozone evolution). However, new cathode materials and... 

Solid Polymer Electrolysis (SPE) and Proton-exchange Membrane Fuel Cell (PEMFC)... 

Equation (3) and (4) mean that the supply of the energetic e is needed to split water. This is the basic principle of water-electrolysis. The PEMFC is just the reverse operation of the SPE. Hydrogen fuel is decomposed into 2e and 2H+ by the catalytic cathode. The protons pass through the solid polymer (electrolyte) and arrive at the anode (A) to react with the electrons and the supplied oxygen. Then, water is produced. The electrons come to A via the external resistance. This fuel cell generates, ideally, about 1 V-direct current power. A stack of the cells is constructed to give the output power with, for example, 25 kW, which is set together to drive the vehicles. 

The perfluorosulfonic acid (Nafion) membrane found its application in fuel cells long before its introduction to the chlor-alkali industry (26-28). The Nafion membrane is used as the solid polymer electrolyte (separator/electrolyte) in fuel cells. Figure 2 shows the schematic of such an SPE fuel cell. 

During the fuel cell reaction, the electrochemical reaction taking place at the cathode of an SPE cell is... 

Applications in Other Electrolyzers. Apart from applications in hydrogen-oxygen fuel cells and water electrolyzers which operate without any supporting electrolyte, SPE electrolyzers are also used efficiently with electrolyte solutions, such as HC1 and Na2SCK+. Recently, LaConti, et al (34), have reported the application of the cell with Nafion as SPE for some important electrochemical processes, including electrolysis of water, HC1, Na2S0 +, and brine solution. 

The hydrated Nafion membrane currently used in SPE cells provides a highly acidic environment, equivalent to a 10 wt% H SOif solution (13). Thus, noble metals or noble metal oxides have to be used as electrocatalysts. It is of particular interest to develop an anion exchange membrane which will transport hydroxyl ions under water electrolysis or fuel cell conditions. This implies that the cell environment would be alkaline, which would enable the substitution of these expensive... 

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