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Synthesis of the Diazonium (Perfluoroalkyl) Benzenesulfonimide Monomer From Nafion Monomer for Proton Exchange Membrane Fuel CellsMei, Hua, D'Andrea, Dan, Nguyen, Tuyet Trinh, Nworie, Chima 01 January 2014 (has links)
One diazonium (perfluoroalkyl) benzenesulfonimide monomer, perfluoro-3, 6-dioxa-4-methyl-7-octene benzenesulfonyl imide, has been synthesized from Nafion monomer for the first time. With trifluorovinyl ether and diazonium precursors, the partially-fluorinated diazonium PFSI monomer can be polymerized and will provide chemically bonding with carbon electrode in proton exchange membrane fuel cells. A systematic study of the synthesis and characterization of this diazonium PFSI monomer has been conducted by varying reaction conditions. The optimized synthesis method has been established in the lab.
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Novel Nanostructure Electrocatalysts for Oxygen Reduction and Hydrogen Evolution ReactionsLuo, Lin January 2019 (has links)
Philosophiae Doctor - PhD / The widespread use of fossil energy has been most convenient to the world,
while they also cause environmental pollution and global warming. Therefore, it
is necessary to develop clean and renewable energy sources, among which,
hydrogen is considered to be the most ideal choice, which forms the foundation of
the hydrogen energy economy, and the research on hydrogen production and fuel
cells involved in its production and utilization are naturally a vital research
endeavor in the world.
Electrocatalysts are one of the key materials for proton exchange member fuel
cells (PEMFCs) and water splitting. The use of electrocatalysts can effectively
reduce the reaction energy barriers and improve the energy conversion efficiency.
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Characterization of Catalyst Coated Membranes using Electron and X-ray MicroscopyGuimarães de Azeredo Melo, Lis 11 1900 (has links)
Proton-Exchange Membrane Fuel Cells are an alternative source of electricity generation for automobiles and stationary power plants. With increasing concerns on environmental issues, recent research has focused on maximizing the efficiency and durability as well as minimizing the costs of fuel cells. One of the main areas of research is optimizing the structure of the cathode catalyst layer. The main driving force of this thesis was the effective visualization of nanostructure of the ionomer, which is responsible for proton conduction in the cathode catalyst layer. However, challenges regarding sample preparation and radiation damage still need to be well understood. Different sample preparation techniques of catalyst inks and catalyst coated membranes were used for Scanning and Transmission Electron Microscopy, such as freeze fracturing, ultramicrotomy and Focused Ion Beam. Comparisons of the microstructure and chemical differences of all components, especially the ionomer, prepared by ultramicrotomy and Focused Ion Beam, was done with Transmission Electron Microscopy and Scanning Transmission X-ray Microscopy applied to the same catalyst coated membrane sample. Detailed spectroscopic information regarding components in both specimens was compared with C 1s and F 1s near edge X-ray absorption spectra recorded in a Scanning Transmission X-ray Microscope. Focused Ion Beam causes extensive damage to the carbon support and ionomer but prepares thinner sections than ultramicrotomy. This work makes it possible to understand the limitations of each sample preparation and compositional analysis technique in order to later apply one of them to image the ionomer in the catalyst layer at the nanoscale, hopefully using tomography techniques. / Thesis / Master of Materials Science and Engineering (MMatSE)
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MODELING THE INTERDEPENDENCE OF ELECTROCHEMICAL AND MECHANICAL PROPERTIES IN PER SULFONATE ACID PROTON EXCHANGE MEMBRANESMalladi, Jaya Sangita 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Proton exchange membrane fuel cells (PEMFC’s) offer an attractive alternative energy resource over traditional fossil fuels. The advantages such as high power density, relatively quick start-up, rapid response to varying loads and low operating temperatures make it a preferred technology option compared to other alternative energy sources. Nafion® by DuPont plays an integral role in the success of PEM fuel cells due to its high proton conductivity and high chemical and thermal stability. This research project aims to study the effect of mechanical and hygro-thermal stresses on the mechanical performance and proton conductivity of the membrane by subjecting it to realistic operating conditions such as those encountered in an automobile.
In this thesis, the time-dependent behavior of the membrane has been modeled using a Prony series and the change in the conductivity due to mechanical loading was experimentally measured. The modeling of both electrochemical and mechanical properties can further be used in studying the degradation properties of the membrane and should guide the development of better membrane materials. Visco-elastic stress relaxation theory has been used in modeling the time-dependent behavior of the specimen. The EIS spectrum has been analyzed using a non-linear least squares method and an equivalent circuit method was also used to fit the spectra.
This project was conducted in three phases. In the first phase a novel test facility was built to perform the experiments. A conductivity measurement test cell that measured
the proton conductivity of a membrane was modeled and manufactured. The second phase included the design of different experiments that helped in modeling the interdependence of electrochemical and mechanical properties of the membrane. In this
process, three series of experiments that tested the electrochemical and mechanical properties of the specimen were conducted. The membrane was held at constant strain and the through plane impedance was measured at different times during the test, specifically before and after stretching at ambient and varying environmental conditions. The membrane was also subjected to both mechanical and hygro-thermal loading conditions during the test. In the third phase, time-dependant mathematical model for the changes in the material properties were developed.
The experimental apparatus thus tested the mechanical and electrochemical properties of the membrane simultaneously while the specimen was being subjected to constant mechanical and varying hygro-thermal conditions. Since the testing method is a novel procedure, the reliability and repeatability of the experimental facility has been verified before conducting the experiments. The experimental apparatus can further be used to test the membrane at varying strain rates and different hygro-thermal loading conditions in a consistent manner. The model developed can be used to analyze the degradation behavior of membrane and also to build better fabrication methods and membrane materials in future.
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Modeling and Evaluation of High Temperature PEM Fuel Cells for Truck ApplicationsWrangstål, Johannes, Ögren, Marcus January 2022 (has links)
With increasing demands on lowering carbon emissions, fuel cell hybrid electric vehicles (FCHEV) have been seen as an alternative to the fossil-fuel driven trucks of today. These would have less emissions and strive to have the same range as any diesel driven transport vehicle. A lot of effort and resources have been put into fuel cell research for incorporation in new powertrains. There are however many different fuel cell types, so the aim of the thesis was to explore two different fuel cell types for use in a FCHEV model.The thesis sets up a model consisting of various subsystems of a high temperature proton exchange membrane fuel cell (HT-PEMFC). Components for the power electronics and a cooling system are also incorporated. The system was then combined with a vehicle model, where a power split between the fuel cell and battery was investigated. The performance of the HT-PEMFC was compared to a low temperature proton exchange membrane fuel cell (LT-PEMFC) on three levels with increasing complexity. These were on a single cell level, stack level and on a vehicle level.The results showed that the HT-PEMFC had worse performance than the LT-PEMFC on both a cell and vehicle level. The power output of an HT-PEMFC was lower for all current densities, meaning more cells were needed in order for the HT-PEMFC to have the same power output as an LT-PEMFC. It did however have a better cooling ability and was a simpler system, which therefore does warrant further investigation on its future use in transport applications. If heat recuperation was investigated further, the HT-PEMFC performance would have been increased to a higher degree than the LT-PEMFC.
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Interaction of Water with the Proton Exchange Fuel Cell MembraneKalapos, Thomas Lawrence 06 April 2007 (has links)
No description available.
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Investigation of Hydrogen Peroxide Production and Transport in a Proton Exchange Membrane Fuel and the Atom Resolved Micro-characterization of its CatalystPelsozy, Michael C. 07 May 2008 (has links)
No description available.
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Non-Precious Metal Electrocatalysts for the Oxygen Reduction Reaction in Proton Exchange Membrane (PEM) Fuel CellsSingh, Deepika 18 August 2014 (has links)
No description available.
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Design, Scale-Up, and Integration of an Ammonia Electrolytic Cell with a Proton Exchange Membrane (PEM) Fuel CellBiradar, Mahesh B. January 2007 (has links)
No description available.
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Model development of a polymer electrolyte membrane fuel cell to predict steady and unsteady behaviorMishra, Bikash 13 December 2008 (has links)
Fuel cells are promising technology to meet the energy need of the future. This alternative energy source is clean and efficient, and with the continuous decrease in fossil fuel resources, one of the best bets towards sustaining our power needs. Fuel cells are being used in automobiles as well as to fulfill portable power needs. In this work a computational model has been developed for fuel cells which can be used to simulate traditional as well as passive proton exchange membrane fuel cell behavior. The model is unsteady, two phase, nonisothermal in nature, and also capable of handling natural convection or buoyancy driven flows. The model also takes into account electrochemical reactions at catalyst sites. The model has been implemented and validated against experiments. It is used to carry out unsteady simulations to study start-up characteristic of proton exchange membrane fuel cells and to follow the behavior of liquid water as well as heat transfer within the cell. The buoyancy model is used to simulate a natural convection region and a passive fuel cell (used for portable applications). Design of passive fuel cells is driven by high temperature regimes and that issue has been further explored.
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