Master Degree in Renewable Energy and Sustainable Development / Mechanical Engineering Department Jordan University of Science and Technology, AL Ramtha, Irbid (Jordan)
Fuel Cell Technology: review paper
Jordan University of Science and Technology, AL Ramtha, Irbid (Jordan)
Hani Khaled Mohammad Alzubi
Research into alternative renewable energy generation is a priority, due to the ever-increasing concern of climate change. fuel cells (FCs) are one potential avenue to be explored, as a partial solution towards combating the over-reliance on fossil fuel-based electricity. Limitations have slowed the advancement of FC development, including low power generation, expensive electrode materials. However, fuel cell technology motivates a variety of benefits, which are barely offered by other energy technologies. The fuel cell can be obtained through natural resources biomass, coal and water, which are abundant. More importantly, most of these are sustainable and realize ecological circulation. Being blessed with a source of renewable energy, fuel cell technology is favorably promoted. Simultaneously, fuel cell technology offers great opportunities to meet the energy consumption demand for its sustainable development. In this proposed review, useful results of leading research in fuel cell relevant research are reviewed. Additionally, its a cleaner and greener alternative source of energy and thus is an important area of research. This paper presents an overview of the two major types of fuel cells and their relation to sustainable management of resources polymer electrolyte membrane fuel cell and the micro fuel cell.
PEMFCs = Polymer Electrolyte Membrane fuel cell
MFCs = Micro Fuel Cells
HE consumption of fossil fuels is dramatically increasing in the last years, which has led to the global climate change. So, fuel cell (FC) has gained much attention in recent decades as a clean and efficient way to generate power due to its high energy efficiency, low operating temperature, and low to zero emissions during its operation.
Extreme weather and climate change are becoming more and more severe compared with the pre-industrial times. It was mainly contributed by the greenhouse gas emission from the extensive usage of fossil fuels. To maintain the current living quality while reserving a better environment for our next generations, renewable energy sources ought to be used. However, based on the current technology development, most of the renewable energy sources encounter problems such as source availability, high cost and intermittency. To supply stable electricity in a clean, reliable and sustainable way, fuel cell is considered a potential candidate to realize a green future. Fuel cell converts chemical energy to electrical energy in a pollutant-free process. The byproducts can be controlled by selecting di?erent types of fuel. Electricity can be produced steadily as long as the fuel is fed to the system continuously. The most commonly available fuel cells are the proton exchange membrane fuel cell (PEMFC) and alkaline fuel cell (AFC), both of which consist of a membrane electrode assembly (MEA).
Hydrogen is the most popular fuel for fuel cells due to its high energy density, small over-potential in oxidation and pollution-free product. Despite these merits of hydrogen fuel, there are still drawbacks that should be taken into consideration. Currently, 96% of the hydrogen is produced from fossil fuels by reforming and pyrolysis which are energy demanding processes. In addition, it is necessary to com- press the hydrogen into vessels for easier transportation due to the low density of hydrogen in ambient air. The energy required for the pro- duction and compression reduces the competitiveness of hydrogen to other green fuels. Besides the production and transportation obstacles, safety is also an important issue to use hydrogen because of the potential explosive reaction with oxygen in air. More importantly, the boil-o? lost during transportation and storage is unavoidable and causes energy wastage.
In contrast to hydrogen, methanol is much safer during the production, handling and usage. The boiling point of methanol is 64.7 °C, which requires no insulation and compression during transportation and storage. Although methanol is also ?ammable, it requires much higher energy to ignite compared with hydrogen. Besides, methanol can be produced from biomass and therefore it is a promising renewable fuel.
Solid oxide fuel cell (SOFC) is a solid-state power generation device, which can directly convert chemical energy stored in fuel and oxidizer to electrical energy with lower pollution emission at high temperature. SOFC can directly utilize di?erent fuels, such as natural gas, biogas and pure hydrogen. Conventional Ni/YSZ composite anode has good catalytic activity and conductivity, and it is widely used for SOFC. However, Ni/YSZ composite anode still faces a lot of problems to be solved urgently, such as carbon deposition and sulfur poisoning. Nickel particles are easily agglomerate and oxidized to NiO at high temperature, which leads to decrease in triple phase boundary (TPB) and catalytic activity.
In this paper will be preliminary focused on two major groups of fuel cells:
1) Polymer Electrolyte Membrane fuel cell (PEMFCs)
1.1 Proton Exchange Membrane Fuel Cells (PEMFCs)
Improved water management of Pt/C cathode modi?ed by graphitized carbon nano?ber in proton exchange membrane fuel cell 
Water management in the cathode is one of the most signi?cant issues in proton exchange membrane fuel cells, especially for long-term stability and dynamic operation in fuel cell vehicles. Therefore, it is critical to design a water-managed/well-fueled cathode layer to overcome signi?cant mass transfer limitations and the corrosion of the carbon support in fuel cells. In this work, they report a simple modi?cation method of the Pt/C cathode using highly graphitized carbon nano?bers for improved water management. Among the graphitized carbon nano?bers with di?erent annealing temperatures, the most hydrophobic one which is prepared by annealing at 2500 °C extremely enhances the power performance, especially at high current densities. Based on the systematical analysis, they can conclude that the graphitized carbon nano?bers act as a gas transport pathway in the cathode layer of membrane electrode assemblies. This study may open up new possibilities for water management and will be helpful for developing high performing proton exchange membrane fuel cell. To improve water management and mass transport, investigations into e?ective cathodes have been performed mainly by three approaches, such as the alteration of the electrode pore structure, the optimization of the ratio of each component in the cathode catalyst layer (CCL), and hydrophobic surface treatment on a CCL or gas di?usion layer (GDL). demonstrated that MEAs incorporated with hydrophilic aluminosilicate ?bers enable fast liquid water removal by the capillary e?ect and lead to a better power density than normal MEAs. As they mentioned, MEAs modi?ed by hydrophobic GCF enhanced mass transport and showed higher cell performance than the normal MEA and MEAs with hydrophilic CNFs. They found that hydro- phobic GCFs improved air transport by providing a water-free region in the cathode. The existence of the proper size of the water-free region in the electrode seems to be more e?ective than only fast liquid water removal during the operation. As indicated, introducing hydrophobic GCFs could be an e?ective water management method in the electrode. Based on the fact that water ?ooding accelerates carbon support corrosion, we can also expect that the incorporation of hydrophobic GCFs into the cathode might be helpful to solve the durability issues in PEMFC.
Recent advancements in applications of alkaline anion exchange membranes for polymer electrolyte fuel cells 
Anion exchange membranes (AEMs) play prominent role in addressing alkaline fuel cell efficiency and cost. Great deal of efforts has been made in the past, particularly during the last couple of years to reach AEMs with high hydroxide conductivity, good chemical/thermal/mechanical stability, fuel cross-over resistance and low cost. Majority of studies reported on traditional quaternary ammonium-based membranes shows performance stability less than 300 h due to the chemical degradation of cationic functional groups. Based on the well-understood degradation mechanism, intensive research efforts on modification of quaternary ammonium-based membranes are adapted. Introducing other functional groups such as imidazolium and guanidinium and use of ionic liquids have also attracted tremendous consideration during the past few years because of their resonant structures and relatively high stability. Hydrophilic-hydrophobic phase separation and ionic phase separated morphology through grafting of alkyl chains with cationic groups are the feasible and effective approach to improve hydroxide conductivity and alkaline stability. Cross-linking between ionic clusters and formation of interpenetrating structures are also important strategies to reduce conductivity-swelling dilemma and improve the dimensional stability of the AEMs. Modifying inorganic materials with cation groups is a logical method to obtain high loading of cationic groups in AEMs as well as maintain the structural stability of AEMs. Polyhedral oligomeric silsesquioxane (POSS), mesoporous silica and titanite nanotube after modification with cationic functionality and incorporated into chemically robust polymer matrix lead to the formation of highly stable AEMs, which impart high power density to fuel cells. Apart from the characteristics of the membrane materials, selection of appropriate preparation methods is also important to achieve desired AEM performances. Polymer blending, pore filling, in-situ polymerization, solvent casting and electrospinning have shown potential in improving the properties of membranes. To date, the reports on the variation of processing conditions on performance are not demonstrated in detail. Hence further optimization of processing conditions is also essential to get improved AEMs. Based on these advances, further innovations in the cation structure, polymer backbone and membrane architecture can direct development of AEMs with further improvement in alkaline stability and put into practical application in fuel cells.
The proton exchange membrane fuel cell for investigation of enhanced performance used in fuel cell vehicles
This study focuses on the parametric analysis of Proton Exchange Membrane Fuel Cells (PEMFC) to enhance its performance used in Fuel cell vehicles. Involves fabrication of membrane electrode assembly at 40% Pt/C loading and experimenting with different parameters, viz, cell temperatures, oxygen and hydrogen ?ow rates and cathode and anode humidi?cation temperatures. The results show that cell temperature has signi?cant effect on the performance of the PEMFC, whereas other parameters produce variation only in the activation polarization region and in the concentration polarization region. A prototype model of FCV, indigenously powered by a fuel cell stack and run continuously without any auxiliary power supply is developed as a viable model for a higher power vehicle. The vehicles performance is studied by conducting various load tests. In this Study, membrane electrode assembly was fabricated with 40% Pt/C loading on the gas diffusion layer. The effect of operating parameters was studied by varying the levels of the required parameter when other parameter values are kept constant. The results show that cell temperature has signi?cant effect on the performance of the PEMFC, whereas other parameters produce variation only in the activation polarization region and in the concentration polarization region. A four wheeled prototype model of FCV, indigenously powered by a fuel cell stack and run continuously without any auxiliary power supply is developed as a viable model for a higher power vehicle. The vehicles performance is studied by conducting various load tests.
1.2 Solid Oxide Fuel cells
High performance metal-supported solid oxide fuel cells with in?ltrated electrodes 
High power density is required to commercialize solid oxide fuel cells for vehicular applications. In this work, high performance of metal supported solid oxide fuel cells (MS-SOFCs) is achieved via catalyst composition, electrode structure, and processing optimization. The full cell con?guration consists of a dense ceramic electrolyte and porous ceramic backbones (electrodes) sandwiched between porous stainless-steel metal supports. The conventional YSZ electrolyte and backbones are replaced with more conductive and thinner 10Sc1CeSZ ceramics. MS-SOFCs are cloistered in a single step and subsequently in?ltrated with Nano catalysts. Five categories of cathode catalysts are screened in full cells, including: perovskites, nickelates, praseodymium oxide, binary layered composites, and ternary layered composites. Various anode compositions are also tested. The conventional LSM cathode catalyst is replaced with more active Pr6O11 and the Ni content of the SDC-Ni anode is increased. Development of the new electrolyte and backbone ceramics, along with selection of cathode and anode catalysts led to approximately 50% increase in power density. Higher conductivity SCSZ electrolyte and backbones were used instead of YSZ, and conventional LSM cathode and SDC-Ni anode were replaced with Pr6O11 cathode and higher Ni content in anode. The power density of 1.56 W cm?2 at 700 °C in air and 2.0 W cm?2 in oxygen (with the cell Rtot of 0.14 ? cm2 at OCV) is the highest cell performance reported for stainless steel MS-SOFCs to date. Multiple cells showed reproducible performance. Cell ASR is shown to be dominated mainly by the cathode polarization and cell con?guration. Performance is very sensitive to cathode composition, but relatively insensitive to the Ni content in SDCN anode. Optimization of individual cell layers (electrolyte and backbone composition, thick- ness, and porosity) also yielded substantial improvements in the MS- SOFC power density
High performance, coking-resistant and sulfur-tolerant anode for solid oxide fuel cell 
Solid oxide fuel cell can e?ciently generate electricity using methane fuel; however, methane cracking at high temperature often results in carbon deposition that leads to degradation of power output. Here, metal-oxide interface is in-situ constructed in LSCM anode to enhance methane oxidation. The anchored interface demonstrated exceptionally high resistance to carbon coking and sulfur poisoning. The peak power density with Cu0.5Fe0.5 -LSCM anode is as high as 0.64 W cm?2 using methane fuel at 850 °C. Electrochemical measurement shows a stable power output under current density of 0.4 A cm?2 using methane fuel even after 10 redox cycles at 850 °C. The in-situ growth of metal-oxide interface not only improves catalytic activity for direct methane oxidation but also enhances the resistance to coking and sulfur poisoning. The best performance with peak power density of 0.64 W cm?2 at 850 °C has been observed for the Cu0.5Fe0.5- LSCM anode using dry methane fuel. The active interfaces prevent metal nanoparticles agglomeration has led to negligible cell performance degradation after high temperature operation for 100 h and 10 redox cycles.
Plastic waste fueled solid oxide fuel cell system for power and carbon nanotube cogeneration 
A process for simultaneous power generation and green treatment of plastic waste by a solid oxide fuel cell (SOFC) integrated with pyrolysis-gasification processes. With an electrolyte-supported configuration, the SOFC delivers a power output of 71 mW cm2 at 800 ?C, which is improved to 280 mW cm2 after applying reforming catalyst. The micro structures of the reforming catalyst before and after operation, the components of the pyrolysis products of plastic waste, and the mechanism and effect of the reforming catalyst to the SOFC are analyzed and discussed in detail. Also, carbon Nano tubes are observed in the catalytic pyrolysis of plastic waste, suggesting it is also a potential technology for electricity-carbon nanotube cogeneration. The feasibility of SOFCs for electricity-carbon Nano tube cogeneration and green treatments of municipal solid wastes simultaneously. A plastic waste fueled SOFC system with reforming catalyst was proposed and evaluated. With (NieAleMg) reforming catalyst, a maximum power density of 280 mW cm2 was achieved using plastic wastes as fuel at 800 ?C, which was only slightly lower than 293 mW cm2 for a hydrogen SOFC and significantly higher than 71 mW cm2 for a plastic wastes SOFC without reforming catalyst. Moreover, with reforming catalyst, the discharging time of the cell operated at a fixed discharging current of 122 mA, increases from 4.0 h to 15 h. It is found that reforming catalyst efficiently converts large molecule hydrocarbons and water into hydrogen and carbon monoxide, and further improve the output performance and discharging time of the SOFC. What’s more, the decline of the discharging time can be attributed to the depletion of the plastic waste. In addition, carbon nanotube is found on the reforming catalyst, suggesting a potential technique for electricity and carbon nanotube cogeneration. The feasibility of a plastic waste SOFC system was demonstrated which provides a novel direction for SOFCs’ practical application and the management of solid waste.