Download or read book Study of the Microstructure and Properties of a PEMFC Catalyst Layer written by Nelly Margareth Cantillo Cuello and published by . This book was released on 2018 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the microstructure and performance of Proton Exchange Membrane Fuel Cells (PEMFCs) with platinum (Pt)-metal-group-free and Pt-based electrodes are evaluated to analyze the effect of the catalyst composition and structure on the electrode properties. In PEMFC systems, the thickness, structure and morphology of the catalyst layer (CL) are integral to cell performance and are particularly significant for cathodes using a non-precious metal catalyst due to higher catalyst loadings and thicker catalyst layers that compensate for the relatively low catalytic activity. An iron (III) porphyrin framework material was synthesized, pyrolyzed and its activity for the oxygen reduction reaction evaluated as a function of the catalyst loading (electrode thickness) and oxygen partial pressure. Various polarization losses were decoupled to reveal limiting processes. The kinetic overpotential was the major contributor. Mass transport contributions to voltage loss increased with higher cathode catalyst loading. Observed performance is discussed in the context of CL structure and morphology, analyzed using microscopy and X-Ray Diffraction. For Pt-based electrodes, the effects of the carbon support and the CL composition were experimentally studied. Machine-prepared cathode CLs with different Pt to carbon (Pt:C) ratios on highly graphitized carbon were prepared using a fixed 3M ionomer to carbon ratio. These were characterized and their PEMFC performance was evaluated. The Pt:C ratio had a significant influence on the CL structure and transport properties. The lowest Pt:C ratio (30:70) exhibited a higher volume of secondary pores and higher proton conductivity over the whole relative humidity range, with higher performance in PEMFC. This correlated with a more homogeneous ionomer distribution throughout the CL, caused by a preferential ionomer/carbon affinity. A study of interactions between 3M ionomer adsorption on a series of carbon supports with various Pt:C ratios provided further evidence for higher affinity of ionomer to the carbon surface. The adsorption isotherm for ionomer on carbon was quantified with two methods. Preferential adsorption on amorphous/graphitic carbon structure boundaries was confirmed. Ionomer adsorption occurs mainly on the secondary pores surface, consistent with previous BET results. Pt nanoparticles exhibited a negative effect on the adsorption process, possibly by blocking ionomer adsorption preferential sites.

Download or read book On the Microstructure of PEM Fuel Cell Catalyst Layers written by Tatyana Sobolyeva and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, the microstructure of conventional catalyst layers of PEM fuel cells (PEMFCs) is investigated and correlated to the catalyst layer water sorption and retention properties, electrochemical properties and fuel cell performance. Two types of conventional carbon support were chosen for investigation: Ketjen Black and Vulcan XC-72. The microstructure of carbon supports, Pt/carbon catalyst powders, and 3-component, Pt/carbon/ionomer catalyst layers is studied in order to evaluate the effects of carbon support microstructure and Nafion ionomer loadings on the resultant CL microstructure. The microstructure of the carbon support is found to be a significant factor in the formation of the structure in the 3-component CLs serving as a rigid porous framework for distribution of Pt and ionomer. It is found that deposition of Pt particles on Ketjen Black significantly changes its porosity possibly by forming at the mouth of the support's micropores, thus affecting its effective microporosity, whereas Pt deposited on Vulcan XC-72 does not significantly affect the support's microporosity. The co-deposition of ionomer in the CL strongly influences porosity of the catalyst layer, especially for pore sizes

Download or read book Catalyst Layer of Polymer Electrolyte Membrane Fuel Cell written by Wang Jingyi and published by LAP Lambert Academic Publishing. This book was released on 2015-10-09 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the process of catalyst ink drops drying in room air is investigated experimentally, which is key to the fabrication of, hence the microstructure formation in, the catalyst layers of polymer electrolyte membrane fuel cells (PEMFCs). The real-time drying process is observed through an optical microscopy and the dried deposition is investigated with a scanning electron microscopy (SEM) and the optical microscopy. This study provides insight into the fundamental understanding of complex drying dynamics during catalyst ink drying, and laid theoretical foundation for further studies on achieving CL microstructure with increased catalyst utilization.

Download or read book Formation and Characteristics of Microstructures from PEM Fuel Cell Catalyst Ink Drying written by Jingyi Wang and published by . This book was released on 2015 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the process of catalyst ink drops drying in room air is investigated experimentally, which is key to the fabrication of, hence the microstructure formation in, the catalyst layers of polymer electrolyte membrane fuel cells (PEMFCs). State-of-the-art catalyst layer in PEMFCs is typically made through the drying of catalyst ink, which is a solvent based colloidal solution with suspended aggregates of nano catalyst particles supported on meso carbons (e.g. C/Pt) and perfluorosulfonic polymer (e.g. Nafion®). Catalyst ink samples are prepared using various Nafion loadings while the C/Pt loading and solid content (C/Pt and Nafion) are held constant. The real-time drying process is observed through an optical microscopy and the dried deposition is investigated with a scanning electron microscopy (SEM) and the optical microscopy. The dried pattern characterizations show the C/Pt agglomerates are more uniformly deposited as the Nafion loading is increased: the deposition at the edge becomes thicker and wider; unique pedal-like pattern with uniform distance is aligned along the inner side of the thicker edge; and the microstructure pattern transits from the concentric rings toward the drop center to heterogeneously detached aggregations. As the Nafion loading is increased, the evaporative cooling induced thermo-capillary flow in the drop varies significantly, from convective outward flow combining with Bernard-Marangoni cell at the center of the drop, to reversed flow coupling with three-dimensional thermo-capillary waves in the annular region near the edge of the drop, which dictates C/Pt agglomerates transport and leads to varies deposition. This study provides insight into the fundamental understanding of complex drying dynamics during catalyst ink drying, and laid theoretical foundation for further studies on achieving CL microstructure with increased catalyst utilization.

Download or read book 2023 International Conference on Energy Engineering written by Zhe Chen and published by Springer Nature. This book was released on with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PEM Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer Science & Business Media. This book was released on 2008-08-26 with total page 1147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.

Download or read book High Temperature Polymer Electrolyte Membrane Fuel Cells written by Qingfeng Li and published by Springer. This book was released on 2015-10-15 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters of the book describe rationalization and illustration of approaches to high temperature PEM systems. Chapters 6 - 13 are devoted to fabrication, optimization and characterization of phosphoric acid-doped polybenzimidazole membranes, the very first electrolyte system that has demonstrated the concept of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications.

Download or read book Polymer Electrolyte Fuel Cells written by Michael Eikerling and published by CRC Press. This book was released on 2014-09-23 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a systematic and profound account of scientific challenges in fuel cell research. The introductory chapters bring readers up to date on the urgency and implications of the global energy challenge, the prospects of electrochemical energy conversion technologies, and the thermodynamic and electrochemical principles underlying the op

Download or read book Structure and Energetics of Nanoparticles and Ionomer Films in Fuel Cell Catalyst Layers written by Qianping He and published by . This book was released on 2013 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improving the durability and utilization efficiency of the platinum-on-carbon (Pt/C) catalyst is of vital importance to the commercialization of the polymer electrolyte membrane fuel cell (PEMFC). This body of work provides molecular level insights to aid the fulfillment of this goal. Chapter 1 describes the use of molecular dynamics (MD) simulation in an effort to understand the Pt/C degradation issue from the nano-adhesion point of view. The roles of catalyst nanoparticle size, shape, Pt/C surface oxidation and the extent of ionomer film hydration are investigated to study their effects on nano-particle adhesion. It is found that the adhesion force strengthens as the Pt size goes up. Nanoparticle of tetrahedral shape exhibits relatively stronger connection with the carbon. The hydroxylated surface enhances nano-adhesion and epoxidized surface diminishes the adhesion. The presence of ionomer film strengthens the adhesion. Chapter 2 uses MD simulations to investigate the microstructure of the catalyst layer, which is essential information needed for increasing the catalyst utilization rate. The ionomer film thickness, hydration level, surface oxidation of Pt/C, presence of Pt or PtO catalysts are key variables studied for their effects on the catalyst layer microstructure and transport properties. It is concluded that the oxidation of the carbon surface and the presence of Pt or PtO catalyst drastically influence the ionomer film configuration and the water distribution on the surface. The thickness of the ionomer film is directly related with its ability of retaining water. Chapter 3 describes experimental work exploring the effect of radiation damage on the microscopic characterization of the catalyst layer of the PEMFCs. It also provides information on the feasibility of in-situ nano-adhesion measurements inside the SEM. It is found that the radiation damage of the catalyst sample usually starts from the interface of Pt/C and primarily occurs in the form of mass loss accompanied by atomic displacement and edge curl. The results indicate the low reliability of the in-situ nano-adhesion measurement. All three chapters serve to expand the fundamental understanding of the microstructure of the catalyst layer, which contribute to the development of a more durable, less expensive and better performing PEMFC.

Download or read book Proton Exchange Membrane Fuel Cells 8 written by T. Fuller and published by The Electrochemical Society. This book was released on 2008-10 with total page 2220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This international symposium is devoted to all aspects of research, development, and engineering of proton exchange membrane (PEM) fuel cells and stacks, as well as low-temperature direct-fuel cells. The intention is to bring together the international community working on the subject and to enable effective interactions between research and engineering communities.

Download or read book Fuel Cells and Hydrogen Production written by Timothy E. Lipman and published by Springer. This book was released on 2018-10-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The expected end of the “oil age” will lead to increasing focus and reliance on alternative energy conversion devices, among which fuel cells have the potential to play an important role. Not only can phosphoric acid and solid oxide fuel cells already efficiently convert today’s fossil fuels, including methane, into electricity, but other types of fuel cells, such as polymer electrolyte membrane fuel cells, have the potential to become the cornerstones of a possible future hydrogen economy. This handbook offers concise yet comprehensive coverage of the current state of fuel cell research and identifies key areas for future investigation. Internationally renowned specialists provide authoritative introductions to a wide variety of fuel cell types and hydrogen production technologies, and discuss materials and components for these systems. Sustainability and marketing considerations are also covered, including comparisons of fuel cells with alternative technologies.

Download or read book Polymer Electrolyte Fuel Cell Durability written by Felix N. Büchi and published by Springer Science & Business Media. This book was released on 2009-02-08 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers a significant number of R&D projects, performed mostly after 2000, devoted to the understanding and prevention of performance degradation processes in polymer electrolyte fuel cells (PEFCs). The extent and severity of performance degradation processes in PEFCs were recognized rather gradually. Indeed, the recognition overlapped with a significant number of industrial dem- strations of fuel cell powered vehicles, which would suggest a degree of technology maturity beyond the resaolution of fundamental failure mechanisms. An intriguing question, therefore, is why has there been this apparent delay in addressing fun- mental performance stability requirements. The apparent answer is that testing of the power system under fully realistic operation conditions was one prerequisite for revealing the nature and extent of some key modes of PEFC stack failure. Such modes of failure were not exposed to a similar degree, or not at all, in earlier tests of PEFC stacks which were not performed under fully relevant conditions, parti- larly such tests which did not include multiple on–off and/or high power–low power cycles typical for transportation and mobile power applications of PEFCs. Long-term testing of PEFCs reported in the early 1990s by both Los Alamos National Laboratory and Ballard Power was performed under conditions of c- stant cell voltage, typically near the maximum power point of the PEFC.

Download or read book Polymer Electrolyte Fuel Cells written by Alejandro A. Franco and published by CRC Press. This book was released on 2016-04-19 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the recent research progress on the fundamental understanding of the materials degradation phenomena in PEFC, for automotive applications. On a multidisciplinary basis, through contributions of internationally recognized researchers in the field, this book provides a complete critical review on crucial scientific topics related

Download or read book Polymer Electrolyte Fuel Cells 11 written by H. A. Gasteiger and published by The Electrochemical Society. This book was released on 2011 with total page 2388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymer Electrolyte Fuel Cell Degradation written by Matthew M. Mench and published by Academic Press. This book was released on 2012 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: For full market implementation of PEM fuel cells to become a reality, two main limiting technical issues must be overcome- cost and durability. This cutting-edge volume directly addresses the state-of-the-art advances in durability within every fuel cell stack component. [...] chapters on durability in the individual fuel cell components -- membranes, electrodes, diffusion media, and bipolar plates -- highlight specific degradation modes and mitigation strategies. The book also includes chapters which synthesize the component-related failure modes to examine experimental diagnostics, computational modeling, and laboratory protocol"--Back cover.

Download or read book Preparation Characterization Properties and Application of Nanofluid written by I. M. Mahbubul and published by William Andrew. This book was released on 2018-09-20 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preparation, Characterization, Properties and Application of Nanofluid begins with an introduction of colloidal systems and their relation to nanofluid. Special emphasis on the preparation of stable nanofluid and the impact of ultrasonication power on nanofluid preparation is also included, as are characterization and stability measurement techniques. Other topics of note in the book include the thermophysical properties of nanofluids as thermal conductivity, viscosity, and density and specific heat, including the figure of merit of properties. In addition, different parameters, like particle type, size, concentration, liquid type and temperature are discussed based on experimental results, along with a variety of other important topics. The available model and correlations used for nanofluid property calculation are also included. Provides readers with tactics on nanofluid preparation methods, including how to improve their stability Explores the effect of preparation method and stability on thermophysical and rheological properties of nanofluids Assesses the available model and correlations used for nanofluid property calculation

Download or read book PEM Fuel Cells written by Gurbinder Kaur and published by Elsevier. This book was released on 2021-11-16 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides a comprehensive introduction to the principles of PEM fuel cell, their working condition and application, and the latest breakthroughs and challenges for fuel cell technology. Each chapter follows a systematic and consistent structure with clear illustrations and diagrams for easy understanding. The opening chapters address the basics of PEM technology; stacking and membrane electrode assembly for PEM, degradation mechanisms of electrocatalysts, platinum dissolution and redeposition, carbon-support corrosion, bipolar plates and carbon nanotubes for the PEM, and gas diffusion layers. Thermodynamics, operating conditions, and electrochemistry address fuel cell efficiency and the fundamental workings of the PEM. Instruments and techniques for testing and diagnosis are then presented alongside practical tests. Dedicated chapters explain how to use MATLAB and COMSOL to conduct simulation and modeling of catalysts, gas diffusion layers, assembly, and membrane. Degradation and failure modes are discussed in detail, providing strategies and protocols for mitigation. High-temperature PEMs are also examined, as are the fundamentals of EIS. Critically, the environmental impact and life cycle of the production and storage of hydrogen are addressed, as are the risk and durability issues of PEMFC technology. Dedicated chapters are presented on the economics and commercialization of PEMFCs, including discussion of installation costs, initial capital costs, and the regulatory frameworks; apart from this, there is a separate chapter on their application to the automotive industry. Finally, future challenges and applications are considered. PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides an in-depth and comprehensive reference on every aspect of PEM fuel cells fundamentals, ideal for researchers, graduates, and students. Presents the fundamentals of PEM fuel cell technology, electrolytes, membranes, modeling, conductivity, recent trends, and future applications Addresses commercialization, public policy, and the environmental impacts of PEMFC in dedicated chapters Presents state-of-the-art PEMFC research alongside the underlying concepts