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1 Advanced Materials Used for the Fabrication of Fuel Cell Systems Mohammed Almeagel UFID# 1684-8311 University of Florida December 15, 2017 2 Abstract The specific purpose of my design project is to identify all the physical components of proton exchange membrane and solid oxide fuel cells such as electrodes, membrane, and fuel. Specifically, this design project describes what materials are used for each component, covers the reasons why that materials is used and describes all the relevant physical properties of the materials. 3 OBJECTIVE There are three major objectives for this design project. The first objective is to introduce fuel cells, to find out how fuel cells work, and to describe the major type of fuel cells generally. The second one is to identify all the physical components of PEM and SOX fuel cells. The final objective is to describe what materials are used for each component and cover the reasons why that material is used. I. INTRODUCTION A. The Definition of Fuel Cells Fuel cells are devices that generate electricity using chemical energy stored in the cells. In fact, this chemical energy comes from an electrochemical reaction of hydrogen which is the basic fuel and oxygen which usually comes from the air. The products of this electrochemical reaction are electricity, water and heat with very little pollution since the fuel is not combusted, unlike internal combustion engines. Both fuel cells and batteries convert chemical energy into electricity. In batteries, the chemical energy is stored inside them and they die once the chemical energy runs out. However, in fuel cells, a continuous outside source of oxygen and fuel is used as chemical energy to generate electricity indefinitely. Therefore, fuel cells will not run out if they have a continuous source of oxygen and fuel. In every fuel cell, there are two electrodes: positive and negative. The fuel goes to the positive electrode (anode) and the oxygen goes to the negative electrode (cathode). Between these electrodes, there is a barrier called electrolyte that carries the electric current and a catalyst to speed up the reaction. 4 B. Applications of Fuel Cells As a matter of fact, fuel cells are used widely and have many applications. The uses of fuel cells can be divided into three major area which is power for transportation, portable power generation, and stationary power generation. 1. Transport application Fuel cells can power cars and buses. Therefore, they can be used instead of the petroleum fuel which has a negative impact on the environment. In fact, now, many vehicle manufacturers are trying to replace the petroleum fuel with fuel cells that is why they have many researchers. As shown in the figure below (See Figure 1), Mirai is an example of a fuel cell vehicle introduced in 2015 by Toyota. Figure 1. Toyota Miari Source: https://insideevs.com/toyota-mirai-fuel-cell-sedan-priced-at-57500-specs-videos/ 2. Portable application In fact, fuel cells can power any portable device. Instead of using a battery which dies ones the chemical energy inside it runs out, fuel cells can be used because they will not die if a continuous source of fuel and oxygen is supplied. Therefore, fuel cells will replace laptop batteries and phones batteries in the future. 5 3. Stationary application One of the largest application of fuel cells is stationary power generation. Stationary fuel cells provide electricity and heat, but they cannot move. They are used widely to power hospitals, schools, and homes and they provide a clean and reliable source of energy. II. THE MECHANISM OF FUEL CELLS The aim of using fuel cells is to produce an electrical current from a chemical reaction which is the key to how fuel cells work. In fact, there are many types of fuel cells and each one of them operates in a different way. However, in general, the principle is same. Firstly, hydrogen which is the basic fuel goes to the positive electrode which takes off the electrons from hydrogen by a chemical reaction. Hence, the hydrogen atoms now carry a positive electrical charge. After that, the work is provided from the electrons. Then, oxygen goes to the negative electrode) and combines with both hydrogen ions which are carried by the electrolyte from the anode and the electrons. The purpose of the electrolyte is to carry the appropriate ions between the cathode and the anode, hence, it plays a major role. As you can see from figure 2 that when hydrogen and oxygen combine, they produce water that exhausts from the cell. Electricity will generate if a continuous outside source of both oxygen and hydrogen is supplied to the cell.
