Proton Polymer Electrolytes in Fuel Cell

Abstract

The electrolyte is one of the main parts of a fuel cell. That is divided into liquid and solid and it is used in both Alkaline and acidulous PH. But with due to kind of electrolyte was used in it, it divides to these parts: 1) Polymeric fuel cell or proton changing. 2) Alkaline fuel cell. 3) Acid phosphoric fuel cell. 4) Melted carbon fuel cell. 5) Solid oxide fuel cell. Only free positive ions move for transfer positive stress through the membrane:For this reason, it is called a reformer membrane. Through the work of fuel cell. Electrolyte must be wet so it's conductance remain. So with attendance to the pressure used in fuel cells, for prevention of steam, the temperature must be kept between 70- 120˚c.In atmosphere pressure, the revenue temp must be lower than 100˚c. It is better to be between 60 to 70˚c. Until remain the quantity of water in the normal case(position). the water transfers in two way at polymeric electrolyte. One is electrical osmotic flow which transfers water and proton from anode to cathode. Another kind of transfer is, the influence of water reversed. (Diffusion flux).It means water will come back from the cathode to the anode. So a balance of water in polymeric electrode deepens on how flowing electrical osmotic and influence of reverse water. The compositions in the polymeric membrane: The electrolyte be used in this kinds of cells (proton polymer) is a solid membrane made of an organic substance that can change Ions. It made from sulfonic acid polymer impregnated with Fluorine or similar polymers. Among them (perfluoro carbon sulfonic acid) that is sedimented on webbed condition (situation). Fluorocarbon polymers are usually expensive and made of them need to special technology. One way to make these kinds of polymers is: fluorocarbon polymer must be extruded to thermoplastic fluoride sulfonyl. To keep properties of substances through the process materials should be in normal conditions. Polymeric electrolytes area different, but in most cases, they use from nafionTM. The thickness of the membrane made of NafionTM is 50 - 175micron. The structure of NafionTM comparatively is hard and permanent and it made from (3) three parts, three main part. 1)Teflon: like carbon-fluorine that have hundred unit of __CF2__CF__CF2__ connected to each other linear. 2) Transversal pat of chain __O__CF2__CF1__O__CF2__ that connects Teflon part to third polymer part. 3) Cluster Ions that consist of sulfuric acid Ions (SO3 -H+). Particulars of polymer membrane: one particular need to the membrane is the thinness of the membrane, when the membrane became thicker, the capacity of the cell be lowed (to be decreased).But thickness lower than 0.1 mm is good.The low resistance of membrane makes the increase of proton transfer capacity. We can use another polymer as membrane like polystyrene sulfonate. But this kind of materials has not (don’t have) suitable chemical resistance for a long time. Among suitable properties of proton interchange membrane, is lack of it sensitive during current and resistance connect or disconnect against separation (change to deference layer). Since low act temperature in these cells, it used from the catalyst in their structure. The best catalyst is platinum and another precious metal, which is deposited a little on the porous carbon.The porosity on electrode makes it easier to diffusion of reactants. For best hydrophobic polymer.platinum particles were deposited on a very thin carbon and they have a diameter about 2 nanometers and prepare spread effect surface for gas reactions. It is mentionable that use of Nanotechnology especially Carbon Nanotubes with direction and certain structure is one of basic forms in properties welfare of this materials in porous membranes for use. Nanopipes, Fueling and similar structures are more suitable for keeping hydrogen and hydrocarbons, to these cells expenses. Also, carbon structures (Nanomaterials-Graphite Nanofibre and Carbonic Nanotubes) are making a Hydrogen potentiality as fuel, they can increase the efficiency of these cells and be economical more and more. Of course in this essay, we explain in detail the way of providing skilled (efficient) polymeric membrane and less expense. After that, we study its problems.Polymeric Electrolyte and Polymeric Membrane with a property of proton interchange: 1) Compositions used in the polymeric membrane. 2) Properties of the polymeric membrane. 3) Way to prepare the polymeric membrane in lab scale. 4) Keeping the humid of the polymeric membrane. 5) Polymeric fuel cell with Catalyst Exothermic system in cold weather. 6) Make of membrane _electrode fuel cell. 7) The way of making membrane electrode cell in lab scale. Figure 1