The Payment of PEM Combustible Nuclear Elements - Term Paper Example

The Cost of PEM Fuel Cell Materials Name: Course: Instructor: Institution: Date: Contents The Cost of PEM Fuel Cell Materials 1 Name: 1 Course: 1 Instructor: 1 Institution: 1 Date: 1 Summary 3 Abstract 4 Introduction 5 Types of fuel cells 6 i.Proton Exchange Membrane 6 ii.Phosphoric acid fuel cell (PAFC) 8 iii.Hydrogen –Oxygen Fuel Cell (Bacon Cell) 9 iv.Molten carbon fuel cells (MCFC) 9 PEM fuel cell development 10 Proton Exchange Fuel Cell material cost and marketing 12 Analysis of the future development of PEM fuel cell 14 References 16 Summary The fuel cells technology has been in use for quite some time now, tracing back to initial forms in early 1960’s. Proton exchange membrane fuel cells employ a polymer ion exchange membrane (Flouro-polymer) as the electrolyte for electrochemical reactions which yield electric current. Even though they showed great success in space exploration, fuel cells systems remained unpopular in most space missions especially in cases where the involved could afford the high costs. The earlier fashions of the same comprised of individual cells which were majorly used for light electronic power applications. Due to intensive research, innovation and technological advancements, Proton exchange membrane fuel cells, which were initially designed for stationary power applications have soon found use in automobile as well as distributed power systems. This has majorly been achieved due to the summative configuration as a result of cell stack technology. There overall cost of the Proton exchange membrane fuel cells alongside the performance characteristics still need modification to aid improvements. This paper thus gives an insight detail on the proton exchange membrane fuel cell, its materials, development and future research on the same technology. Abstract Fuel cells were initially developed by General Electric Company of the United States with a major aim of using them to power gadgets for space exploration. With time, modification and improvements were done the initial designs to enhance performance and thereby introducing the concept of a heat resistant membrane. Subsequent innovation led to summation of individual cells to create cell stacks. Improved performance encouraged mass production of proton exchange membrane fuel cells. Proton Membrane Exchange Fuel Cells (PEMFC) has been widely conceptualized as environmentally friendly energy sources. They use a polymer membrane between two electrodes as the electrolyte. Some of the outstanding features, PEM have low operating temperatures and have ability to develop high output power density. This owes to the explanation that the contact areas between the electrode catalyst and ion-exchange membrane can be adjusted accordingly. Key words: Fuel cells, Proton Membrane Exchange, Power density, polymer membrane, electrodes, electrolyte Introduction Fuel cells is a collective term used to refer to such devices that convert stored chemical energy in a fuel into electrical energy to drive prime movers in the presence of oxygen gas or any other oxidizing agent. The whole scenario takes place in a pollutant free environment hence they are considered environmentally friendly. A single fuel cell comprises of several individual cells which are arranged together to form a fuel stack. Each of the cells within the cell stack consists of an anode, a cathode and an electrolyte. The electrochemical reaction that yields electrical energy is usually initiated by a simple bubbling or introduction of a hydrogen-rich fuel. Such fuel could be clean natural gas or biogas. The end products for the electrochemical reaction in the fuel stack are heat, water and electric current. Fuel cells have been widely used as sources of portable auxiliary power, stationery distribute power as well as central power applications and automotive power sources. In several instances, fuel cells have been cited as the most viable solution and technology for environmental conservation. The proton exchange membrane (PEM) fuel cell in particular has been widely adopted and used for stationery distributed power applications, transportation and some small to medium scale applications. Fuel cells find new uses day in day out. Each new use requires for a certain configuration of the fuel cell and therefore different proton exchange membrane (PEM) fuel cells and membrane assemblies have been developed from such specific applications. Types of fuel cells There exists a wider range of fuel cells. However, regardless of the type and configuration all fuel cells operate on a similar principle. They all comprise of three fundamental segments; the anode, the cathode and the electrolyte. The working of any fuel cell involves two chemical reactions which occur at the surfaces of the three segments. At the end of the three reactions, the fuel is consumed while electrical energy is generated with either carbon iv oxide or water given off as a byproduct. i. Proton Exchange Membrane Proton exchange Membrane (PEM) fuel cells, also referred to as Polymer exchange membrane fuel cells usually run on pure (99.999%) hydrogen fuels. It is the most commonly and widely used type of fuel cell. The Proton exchange Membrane fuel cell usually combines the hydrogen fuel with the oxygen from the atmosphere in a chemical reaction to produce Water, heat and electric current. When hydrogen gas is delivered to the anode (positive terminal) of the membrane electrode, it is split up with the help of a catalyst into protons and electrons, a process called oxidation. The ions generated in this The electrons on the other hand go round an external circuit thereby creating an electric current to rejoin the hydrogen ions on the cathode. The half-cell equations for these reactions are given by: At the Anode: 2H2 »» 4H+ + 4e- At the cathode: O2 + 4H+ + 4e- »» 2H2O Each individual cell has a generation capacity of around 1.1 volts. In order to obtain the required voltage, several individual cells are combined into a stack whose individual voltages sum up to the required voltages. In a stack, individual cells are separated by bipolar plates. The bipolar plates also act as surface for hydrogen fuel distribution as well as providing a means of extracting the generated electric current. A simple Proton exchange Membrane (PEM) fuel cell Water management is a crucial aspect that affects the general performance and efficiency of Proton Exchange Membrane fuel cells. For instance, insufficient water available in the membranes greatly hampers proton conductivity thereby increasing cell resistance. On the other hand, excessive amounts of water cathode results into “Cathode flooding”, a phenomenon that hinders the flow of oxygen through the porous carbon electrode. Hence the concept of electro-osmotic drag becomes a key note aspect of the Proton Exchange Membrane fuel cell performance. Despite provision of ambient operating temperatures, most Proton Exchange Membrane fuel cells usually have low efficiency due to poor electro-osmotic drag within the cell and therefore making the concept an important component of future research and innovation. Proton Exchange Membrane Fuel Cells have been established to be the most versatile type of fuel cells being produced as at the moment. The cells find applications in a wide range of uses such as space crafts, stationary power appliances, transport and portable power applications. The mass production of such fuels has been perhaps accelerated by the fact that proton exchange membrane cells have ability to generate the highest possible power for any given unit weight or volume of a fuel cell. Some other outstanding features that give such fuels a wide range of applications include light weight, short start up time (They start almost instantaneously), quick response to load variations, compactness, high cold start capabilities as well as possession of high power densities. One major notable feature of the Proton Exchange Membrane is ability to provide efficient and hassle-free means of energy recovery from hydrogen which is usually produced as a by-product in chlor-alkali plants. ii. Phosphoric acid fuel cell (PAFC) The initial design of this type of fuel was done way back in i961 through joint efforts of G.V. Elmore and H.A.Tanner. This type of fuel cell uses phosphoric acid as the major electrolyte (nonconductive) which provides a path for movement of hydrogen ions from the anode to the cathode. The optimum operating temperatures for phosphoric fuel cells is about 150 to 200 degrees Celsius; slightly higher temperatures than this will often result into excessive energy losses. For this reason phosphoric acid fuel cells require elaborate heat control systems to efficiently manage the high amounts of heat generated in the cell. Most of the available heat losses in a phosphoric acid fuel cell occur in form of dissipated heat. Such generated heat is efficient enough to drive most domestic thermal energy consumption systems or even produce steam for air conditioning systems. Therefore in order to increase the efficiency of such cells, a thermal application must be identified to make use of the excess heat generated. A major setback associated with this kind of cells is the use of an acidic electrolyte which in turn increases the corrosion or oxidation of metallic components exposed to contact with phosphoric acid. iii. Hydrogen –Oxygen Fuel Cell (Bacon Cell) They are also called alkali fuels. This type of fuel cells is considered among the initial models of fuel cells that were used as primary sources of electrical energy as early as during the Apollo space exploration. This cell is made up of two carbon electrodes impregnated with a catalyst which acts as an electrolyte immersed in a concentrated solution of potassium hydroxide or sodium hydroxide. For the cell to produce electrical energy, hydrogen gas and water are bubbled into the electrolyte through the carbon rods so as to provide the necessary ions for the electrochemical reactions at the anode and cathode. The cell operates best at temperatures between 343 degrees kelvin to 413 degrees kelvin thereby producing a potential of about 0.9 . in this case, a cell stack of hydrogen-oxygen fuel cells will comprise of more individual cells than an equivalent stack of proton exchange fuel cell for the same capacity. iv. Molten carbon fuel cells (MCFC) This type of fuel cells requires high operating temperatures of about 650 degrees Celsius. Some of the commonly available molten carbon fuel cells compatible fuels include natural gas, biogas and gas produced from coal. They use sodium carbonate, magnesium carbonate or any other salts capable of liquefying at higher temperatures as electrolytes alongside insulated carbon rods as electrodes. Molten carbon fuel cells can be used in the conversion of fossil fuel into hydrogen- dominant gas hence no need for external production of hydrogen required for the reactions. Molten carbon fuel cells are at times said to be self-starting since they do not necessarily require bubbling of hydrogen in to the cell from an external source. Molten carbon fuel cells have several advantages over other fuel cells. For instance, they are not susceptible to carbon coking due to their strong resistance to impurities. They subsequently have a fuel to electricity of about 50% which sometimes can exceed this. One major drawback of molten carbon fuel cells s that they have slow start-up times due to their high operating temperature. This makes systems that run on molten carbon fuel cells unsuitable for mobile applications hence Molten carbon fuel cells are usually used for stationary fuel cell purposes. They subsequently have a short life span due to the effect of the high-temperature and corroding effects of the carbonate electrolyte at the anode and cathode. PEM fuel cell development Figure: Development of a proton Exchange Membrane Fuel cell (PEMFC) The proton Exchange Membrane –Membrane Electrode (PEM-MEA) Assembly involves a sandwiching of the proton exchange membrane in between two electrode rods, embedded with platinum catalyst within their structure. Materials commonly used to make Proton Exchange Membrane Fuel Cell include carbon cloth or carbon fiber papers. More different terms are used to refer to these electrodes depending on the assembling and fabrication company. The proton Exchange Membrane (PEM) is basically a flouro-polymer barrier which allows diffusion of protons across its surface at the same time acting as an electrical insulation between the two electrodes. The barrier allows free movement of protons from the anode to the cathode but forces the electrons from the cathode to anode to go through the conductive path. The electrodes, which constitute the anode and the cathode, are further insulated to prevent any electrical conductivity between their surfaces. To ensure a compact structure, the electrodes are heat pressed onto the Proton Exchange Membrane. Platinum is the most commonly used catalyst in PEM fuel cells. Nevertheless, other metallic elements in the platinum group such as Ruthenium and titanium can still produce similar performance characteristics. However, a major disadvantage of these catalysts is there high susceptibility to carbon poisoning hence reducing the efficiency of the whole fuel cell system.in fact this is the major reason behind the intensive researches to come up with catalysts that use low cost materials and are cheaper in the long run. Proton Exchange Fuel Cell material cost and marketing Materials for Proton Exchange Membrane fuel cell system Globally, the market value of individual components for assembly and production of Proton Exchange Membrane fuel cell system was estimated to be $383 in the year 2010. This figure was however projected to grow at an annual rate of 20.6% and was therefore expected to hit the $977 million by the year 2015. The components covered under this estimate include the cell membrane, bipolar plates, catalysts, electrodes and the catalyst ink. Among the components, platinum catalysts had the highest estimated value of about $200 million and had a potential of clocking the $424 million mark by the year 2015 at an annual growth rate of 16.2%. Summary Figure: Global Proton Exchange Fuel Cell Membrane Electrode Assembly Market through 2015 ($ Millions) As at December 2013, the United States Department of energy estimated that it would cost an approximate of US$67 per kilowatt to make an 80-kW automotive Proton Exchange Membrane fuel cell system. This was made on an assumption of a 100,000 automotive units per year volume production. Subsequently, if the volume production could rise to 500, 000 automotive units per year, then it would cost an estimated US$55 per kilowatt. Most companies producing fuel cells have now embarked on research and innovations to reduce the amount of raw materials such as platinum subsequently needed in the production of each individual fuel cell. An example of such material reduction was done by Ballard Power Systems which managed to make Proton Exchange Membrane fuel cells using a catalyst enhanced with carbon silk. Carbon silk was designed to allow a 30% equivalent to 1mg/cm2 to 0.7mg/cm2 reduction in the overall amount of platinum required without necessarily affecting the performance characteristics of the Proton Exchange Membrane fuel cell. A further modification with the aim of reducing the overall cost through material reduction involves use of metal-free electro-catalysts. Such catalysts are usually cheap doped carbon nanotubes whose cost is even 1% less that of platinum but have equal or superior performance as platinum catalysts. Analysis of the future development of PEM fuel cell In essence, the typical fuel for Proton Exchange Membrane fuel cells should be hydrogen gas which exists in nature as a constituent of water molecules as well as in organic compounds. Typical Proton Exchange Membrane fuel cells which use platinum as the electrolyte catalyst usually experience component corrosion and damage in the instances where carbon compounds are introduced in the fuel gas. The fuel processors are therefore designed and constantly checked to see that they supply carbon monoxide-free fuel to the cell. This is one of the major research areas in the future development of Proton Exchange Membrane fuel cells. Research is still being undertaken by various institutions and individuals to increase the performance characteristics of Proton Exchange Membrane fuel cells. Such research is aimed at a number of components and key performance indicators. For instance, there is need to design and implement a both scalable and greatly improved fabrication method for making membranes, electrodes and bipolar plates. This should also go in line with development of catalysts and supports with reduced metal enhancement, durable and cheaper. The two research concepts will be as a move to improve efficiency in production of Proton Exchange Membrane fuel cell as well as reduce on the overall production costs. Virtually all Proton Exchange Membrane fuel cells use platinum as a catalyst. Platinum is one of the precious metals and as a result, it is expensive. There is therefore impending need to use non precious metal catalysts which are cheaper hence cutting down the overall cost. Research should also help develop membrane with more and increased ionic activity so as to increase the rate of lector-chemical reaction; perhaps reduce the dire need for a catalyst, reduced thickness and more durable. Finally such research also aims at production and use of bipolar plates with greatly improved gas circulation, higher conductivity, cheap and resistant to corrosion by the electrolyte. Future development of the Proton Exchange Membrane fuel cell should thus focus on certain key elements among them identification of new for fabrication and manufacture of the cell membrane, cathode, catalyst and support, bipolar plates as well as subsystems components. Future development also ought to pay attention to developing a high temperature and low humidity polymer electrolyte which should operate at about 120 degrees Celsius and offer higher tolerance to impurities especially corrosion by carbon compounds. References Bullis, Kevin. (2009-04-02) A Catalyst for Cheaper Fuel Cells. Technologyreview.com. Retrieved on 2014-10-21. G. Hoogers (2003). Fuel Cell Technology Handbook. Boca Raton, FL: CRC Press. pp. 6–3. G. Hoogers (2003). Fuel Cell Technology Handbook. Boca Raton, FL: CRC Press. pp. 6–3. Grove, William Robert. "On Voltaic Series and the Combination of Gases by Platinum", Philosophical Magazine and Journal of Science vol. XIV (1839), pp. 127–130 H.I. Onovwiona and V.I. Ugursal. Residential cogeneration systems: review of the current technology. Renewable and Sustainable Energy Reviews, 10(5):389 – 431, 2006. Kakati B. K., Mohan V., (208)"Development of low cost advanced composite bipolar plate for P.E.M. fuel cell", Fuel Cells, 08(1): 45–51 Koraishy, Babar (2009). "Manufacturing of membrane electrode assemblies for fuel cells". : Singapore University of Technology and Design Lee, J. S. et al. (2006). "Polymer electrolyte membranes for fuel cells". Journal of Industrial and Engineering Chemistry 12: 175–183. Lee, J. S. et al. (2006). "Polymer electrolyte membranes for fuel cells". Journal of Industrial and Engineering Chemistry 12: 175–183 N. Tian, Z.-Y. Zhou, S.-G. Sun, Y. Ding, Z. L. Wang (2007). "Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity". Science 316 (5825): 732–735 N. Tian, Z.-Y. Zhou, S.-G. Sun, Y. Ding, Z. L. Wang (2007). "Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity". Science 316 (5825): 732–735 NAIDI, S. M. J., & MATSUURA, T. (2009). Polymer membranes for fuel cells. New York, Springer Verlag. S. Alayoglu, A. U. Nilekar, M. Mavrikakis, B. Eichhorn. Ru–Pt core–shell nanoparticles for preferential oxidation of carbon monoxide in hydrogen (2008). "Ru–Pt core–shell nanoparticles for preferential oxidation of carbon monoxide in hydrogen". Nature Materials 7 (4): 333–338 V. R. Stamenkovic, B. Fowler, B. S. Mun, G. Wang, P. N. Ross, C. A. Lucas, N. M. Marković. Activity on Pt3Ni(111) via increased surface site availability (2007). "Improved Oxygen Reduction Activity on Pt3Ni(111) via Increased Surface Site Availability". Science 315 (5811): 493–497 Von Helmolt, R.; Eberle, U (20 March 2007). "Fuel Cell Vehicles:Status 2007". Journal of Power Sources 165 (2): 833 Wang, J.Y.; Wang, H.L. (2012). "Discrete approach for flow-field designs of parallel channel configurations in fuel cells". Int. J. of Hydrogen Energy 37 (14): 10881–10897. Read More

Fuel cells have been widely used as sources of portable auxiliary power, stationery distribute power as well as central power applications and automotive power sources. In several instances, fuel cells have been cited as the most viable solution and technology for environmental conservation. The proton exchange membrane (PEM) fuel cell in particular has been widely adopted and used for stationery distributed power applications, transportation and some small to medium scale applications. Fuel cells find new uses day in day out.

Each new use requires for a certain configuration of the fuel cell and therefore different proton exchange membrane (PEM) fuel cells and membrane assemblies have been developed from such specific applications. Types of fuel cells There exists a wider range of fuel cells. However, regardless of the type and configuration all fuel cells operate on a similar principle. They all comprise of three fundamental segments; the anode, the cathode and the electrolyte. The working of any fuel cell involves two chemical reactions which occur at the surfaces of the three segments.

At the end of the three reactions, the fuel is consumed while electrical energy is generated with either carbon iv oxide or water given off as a byproduct. i. Proton Exchange Membrane Proton exchange Membrane (PEM) fuel cells, also referred to as Polymer exchange membrane fuel cells usually run on pure (99.999%) hydrogen fuels. It is the most commonly and widely used type of fuel cell. The Proton exchange Membrane fuel cell usually combines the hydrogen fuel with the oxygen from the atmosphere in a chemical reaction to produce Water, heat and electric current.

When hydrogen gas is delivered to the anode (positive terminal) of the membrane electrode, it is split up with the help of a catalyst into protons and electrons, a process called oxidation. The ions generated in this The electrons on the other hand go round an external circuit thereby creating an electric current to rejoin the hydrogen ions on the cathode. The half-cell equations for these reactions are given by: At the Anode: 2H2 »» 4H+ + 4e- At the cathode: O2 + 4H+ + 4e- »» 2H2O Each individual cell has a generation capacity of around 1.1 volts. In order to obtain the required voltage, several individual cells are combined into a stack whose individual voltages sum up to the required voltages.

In a stack, individual cells are separated by bipolar plates. The bipolar plates also act as surface for hydrogen fuel distribution as well as providing a means of extracting the generated electric current. A simple Proton exchange Membrane (PEM) fuel cell Water management is a crucial aspect that affects the general performance and efficiency of Proton Exchange Membrane fuel cells. For instance, insufficient water available in the membranes greatly hampers proton conductivity thereby increasing cell resistance.

On the other hand, excessive amounts of water cathode results into “Cathode flooding”, a phenomenon that hinders the flow of oxygen through the porous carbon electrode. Hence the concept of electro-osmotic drag becomes a key note aspect of the Proton Exchange Membrane fuel cell performance. Despite provision of ambient operating temperatures, most Proton Exchange Membrane fuel cells usually have low efficiency due to poor electro-osmotic drag within the cell and therefore making the concept an important component of future research and innovation.

Proton Exchange Membrane Fuel Cells have been established to be the most versatile type of fuel cells being produced as at the moment. The cells find applications in a wide range of uses such as space crafts, stationary power appliances, transport and portable power applications. The mass production of such fuels has been perhaps accelerated by the fact that proton exchange membrane cells have ability to generate the highest possible power for any given unit weight or volume of a fuel cell. Some other outstanding features that give such fuels a wide range of applications include light weight, short start up time (They start almost instantaneously), quick response to load variations, compactness, high cold start capabilities as well as possession of high power densities.

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