Download or read book Probing Ion Conducting Domains and Localizing Catalysts in Proton Exchange Membrane Fuel Cells written by James Ryan O'Dea and published by . This book was released on 2010 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells convert chemical energy into electrical energy at high efficiencies with few to no emissions. From a chemistry and materials standpoint, phenomena associated with the electrolyte and catalysts are key to improving the performance and lowering the cost of these devices. Towards this end, atomic force microscopy (AFM) was used to probe the chemical domains responsible for proton transport. Phase imaging was used to gain quantitative information regarding the size and distribution of proton conducting domains and it was found that the nature of tip-sample interaction forces strongly affects the resolution and subsequent interpretation of such domains. For a Nafion perfluorosulfonic acid electrolyte, dramatic differences in domain morphology were observed at hydrated and dehydrated conditions. Novel AFM current imaging was performed on a half fuel cell in which a platinum coated tip served as a nanoscale cathode to probe the electrochemical activity at the surface of a polymer electrolyte. Comparison of current and phase images of a Nafion membrane revealed that not all aqueous surface domains are electrochemically active to the same extent. Phase images and point-by-point current-voltage measurements suggest that large domains (>100 nm2) with a high degree of surface connectivity are most active. Electrochemical pulse deposition was used to localize platinum catalysts at these domains, resulting in a device with a platinum loading of 2 mug/cm2 and a maximum power density of 120 mW/cm2.
Download or read book Proton Conducting Membrane Fuel Cells II written by Shimshon Gottesfeld and published by The Electrochemical Society. This book was released on 1999 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proton Conducting Membrane Fuel Cells IV written by and published by The Electrochemical Society. This book was released on 2006 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proton Conducting Membrane Fuel Cells written by and published by . This book was released on 2005 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proton Exchange Membrane Fuel Cells 6 written by Thomas Francis Fuller and published by The Electrochemical Society. This book was released on 2006 with total page 1385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The symposium was devoted to all aspects of research development and engineering of proton exchange membrane fuel cells. Three subareas were covered: materials and electrode processes, fuel cell systems, and durability.
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 Proton Exchange Membrane Fuel Cells written by Alhussein Albarbar and published by Springer. This book was released on 2017-11-17 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the characteristics of Proton Exchange Membrane (PEM) Fuel Cells with a focus on deriving realistic finite element models. The book also explains in detail how to set up measuring systems, data analysis, and PEM Fuel Cells’ static and dynamic characteristics. Covered in detail are design and operation principles such as polarization phenomenon, thermodynamic analysis, and overall voltage; failure modes and mechanisms such as permanent faults, membrane degradation, and water management; and modelling and numerical simulation including semi-empirical, one-dimensional, two-dimensional, and three-dimensional models. It is appropriate for graduate students, researchers, and engineers who work with the design and reliability of hydrogen fuel cells, in particular proton exchange membrane fuel cells.
Download or read book Proton Exchange Membrane Fuel Cells written by Hui Li and published by CRC Press. This book was released on 2010-04-14 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-scale commercialization of proton exchange membrane fuel cell (PEMFC) technology has been hindered by issues of reliability, durability, and cost, which are all related to the degradation of fuel cell performance. This degradation often has root causes in contamination from fuel, air streams, or system components. With contributions from inte
Download or read book Proton Exchange Membrane Fuel Cells written by Inamuddin and published by John Wiley & Sons. This book was released on 2023-02-10 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: PROTON EXCHANGE MEMBRANE FUEL CELLS Edited by one of the most well-respected and prolific engineers in the world and his team, this book provides a comprehensive overview of hydrogen production, conversion, and storage, offering the scientific literature a comprehensive coverage of this important fuel. Proton exchange membrane fuel cells (PEMFCs) are among the most anticipated stationary clean energy devices in renewable and alternative energy. Despite the appreciable improvement in their cost and durability, which are the two major commercialization barriers, their availability has not matched demand. This is mainly due to the use of expensive metal-catalyst, less durable membranes, and poor insight into the ongoing phenomena inside proton exchange membrane fuel cells. Efforts are being made to optimize the use of precious metals as catalyst layers or find alternatives that can be durable for more than 5000 hours. Computational models are also being developed and studied to get an insight into the shortcomings and provide solutions. The announcement by various companies that they will be producing proton exchange membrane fuel cells-based cars by 2025 has accelerated the current research on proton exchange membrane fuel cells. The breakthrough is urgently needed. The membranes, catalysts, polymer electrolytes, and especially the understanding of diffusion layers, need thorough revision and improvement to achieve the target. This exciting breakthrough volume explores these challenges and offers solutions for the industry. Whether for the student, veteran engineer, new hire, or other industry professionals, this is a must-have for any library.
Download or read book Chemical Modification of Fuel Cell Catalysts and Electrochemistry of Proton Exchange Membrane Fuel Cell Electrodes written by E. Bradley Easton and published by . This book was released on 2003 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Control of Ionomer Distribution in Roll to Roll Coated Fuel Cell Catalyst Layers written by and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cell catalyst layers are a complex mixture of catalyst particles and ion-conducting polymers. The performance of catalyst layers is highly dependent on microstructure, which must balance proton and electron conduction with gas transport. As fuel cells transition from the laboratory to industrial production for vehicles and other applications, there is a need to understand how manufacturing processes impact the microstructure and, ultimately, the performance of catalyst layers. In this work, we have focused on the roll-to-roll coating of catalyst layers for proton exchange membrane fuel cells. The catalyst layers are responsible for the electrochemical reactions that enable power production. In these devices the catalyst is commonly a Pt nanoparticle supported on porous carbon blacks. The ion conducting polymer, or ionomer, is typically a perfluorosulfonic acid. The most common being Nafion. To fabricate the catalyst layer, the catalyst particles are dispersed in an ink with the ionomer and cast to form the catalyst layer. Commonly, laboratory samples are prepared using spray coating or hand painting, which effectively coat many thin layers to achieve the desired catalyst layer thickness. This creates catalyst layers with uniform distributions of materials throughout the thickness of the full catalyst layer. In contrast, roll-to-roll methods, like slot die, gravure or screen printing, coat the catalyst layer as a single wet film. As the film dries, ink constituents are able to segregate, leading to a heterogeneous distribution of materials through the thickness of the layer. It is also known that the choice of solvent and drying rate can affect the morphology of the catalyst layer. Thus, there is a need to understand how ink formulation and the drying process influence the distribution of materials and catalyst layer morphology. Here, we have explored the influence of solvent and drying rate on morphology of roll-to-roll coated catalyst layers. We show the development of the Kelvin probe method as a rapid screening technique for qualitative analysis of ionomer distribution. We also utilize nano X-ray computed tomography to visualize electrode structure and to quantify particle-size and pore-size distributions, thickness-dependent ionomer distribution, tortuosity, and effective transport properties. We find that solvent has a strong influence on ionomer distribution, with less of an effect on porosity. Conversely, drying temperature has a strong influence on porosity, but less influence on ionomer distribution. Finally, we utilize in situ fuel cell performance testing and other advanced diagnostics to quantify the impact of catalyst layer properties on fuel cell performance and demonstrate that roll-to-roll coating is capable of coating high performance catalyst layers in multi-meter lengths.
Download or read book Thin film Catalysts for Proton Exchange Membrane Water Electrolyzers and Unitized Regenerative Fuel Cells written by Peter Kúš and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This work revolves around the hydrogen economy and energy-storage electrochemical systems. More specifically, it investigates the possibility of using magnetron sputtering for deposition of efficient thin-film anode catalysts with low noble metal content for proton exchange membrane water electrolyzers (PEM-WEs) and unitized regenerative fuel cells (PEM-URFCs). The motivation for this research derives from the urgent need to minimize the price of such electrochemical devices should they enter the mass production. Numerous experiments were carried out, correlating the actual in-cell performance with the varying position of thin-film catalyst within the membrane electrode assembly, with the composition of high-surface support sublayer and with the chemical structure of the catalyst itself. The wide arsenal of analytical methods ranging from electrochemical impedance spectroscopy through electrochemical atomic force microscopy to photoelectron spectroscopy allowed the description ofthe complex phenomena behind different obtained efficiencies. Systematic optimizations led to the design of a novel PEM-WE anode thin-film iridium catalyst which performs similarly to the standard counterparts despite using just a fraction of their noble metal content. Moreover, the layer-by-layer approach resulted in the design of a Ir/TiC/Pt bi-functional anode for PEM-URFC which is able to operate in both the fuel cell and electrolyzer regime and thus helps to cut the cost of the whole conversion system even further.
Download or read book Nano enabled Catalyst for High Power Proton Exchange Membrane Fuel Cells written by Jiefeng Lin and published by . This book was released on 2010 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimization and Characterization of Proton exchange Membrane Fuel Cells Based on Novel Hydrocarbon Ionomers written by Hien Nguyen and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Hydrogen is a critical energy carrier for defossilising the transportation sector. Proton-exchange membrane (PEM) fuel cells represent a pivotal technology for heavy-duty vehicles, in particular. These fuel cells enable the conversion of hydrogen into electrical energy, with the only by-product being water. State-of-the-art PEM fuel cells rely on perfluorosulfonic acid (PFSA) as cation-exchange material. The synthesis of PFSAs is complex, hazardous and expensive, which limits their production to a few select facilities globally, driving up costs even at high volumes. In recent years, there has been a growing concern over the high level of irreversible environmental damage caused by perfluorinated substances. Leading corporations, such as DuPont and 3M, have faced numerous lawsuits for over a decade. To address these concerns, 3M announced in December 2022 that it would exit the perfluorinated substances business by the end of 2025. An alternative to PFSAs is hydrocarbon ionomers, which offer potentially lower material costs, high thermo-mechanical stability at high operating temperatures, and reduced environmental concerns. While replacing PFSA with hydrocarbon ionomers can make fuel cells more sustainable, it has been observed in earlier studies to compromise performance. The primary objective of this study was to bridge the performance and knowledge gap between hydrocarbon and PFSA-based PEM fuel cells. This was achieved by employing a recently commercialized ionomer called "Pemion". Leveraging this innovative material, this work succeeded in developing a fully hydrocarbon-based fuel cell with outstanding performance, representing a significant breakthrough in 2021. To realize this outcome, the study began with a comprehensive literature review,[1] that identified the most significant limitations associated with hydrocarbon-based fuel cells and proposed strategies for their future commercialization. Systematic know-how transfer was then implemented from the field of PFSA-based materials, encompassing process adaptations and extensive optimization of the catalyst layer to advance towards the state-of-the-art performance of PFSA-based fuel cells. A combination of an ultra-thin monolithic membrane (7 μm) and an optimized ink composition with a platinum-cobalt catalyst enabled a comparable peak performance (> 2 W cm-2) to state-of-the-art PFSA reference cell under optimized laboratory conditions: H2/O2, 80 °C, fully humidified gases and ambient pressure. Electrochemical characterizations under various operating conditions show that the hydrocarbon-based cells' performance is more sensitive to changes in relative humidity than the PFSA reference cell.[2] Based on the proof-of-concept, two follow-up improvement pathways have been identified to improve performance and understanding in hydrocarbon-based fuel cells. First, ionomer gradient catalyst layers have been introduced for hydrocarbon-based fuel cells.[3] A two-fold higher ionomer content compared to the optimized one in 25 % of the catalyst layer at the membrane interface improved the performance by up to 35 % in application-relevant conditions, i.e. reduced humidity, while maintaining high peak performance under the same conditions. Second, different conditioning procedures were investigated on hydrocarbon-based fuel cells for the first time. A novel conditioning procedure developed for hydrocarbon-based fuel cells was found to improve the typically lower performance at low current densities of hydrocarbon-based fuel cells the most efficiently.[4] Based on the findings, fuel cells that use Pemion have been shown to perform similarly to those that use PFSA, but further improvements are required for their application in fuel-cell electric vehicles. To continue improving these fuel cells, it is important to find a balance between effective proton conductivity and mechanical integrity of the ionomer in the catalyst layer for efficient performance under different humidity levels. Reference: [1] Hien Nguyen, Carolin Klose, Lukas Metzler, Severin Vierrath, and Matthias Breitwieser. Fully hydrocarbon membrane electrode assemblies for proton exchange membrane fuel cells and electrolyzers: An engineering perspective. Advanced Energy Materials, 12(12):2103559, 2022. doi:10.1002/aenm.202103559. [2] Hien T. T. Nguyen, Florian Lombeck, Claudia Schwarz, Philipp A. Heizmann, Michael Adamski, Hsu-Feng Lee, Benjamin Britton, Steven Holdcroft, Severin Vierrath, and Matthias Breitwieser. Hydrocarbon-based pemionTM proton exchange membrane fuel cells with state-of-the-art performance. Sustainable Energy & Fuels, (5):3687-3699, 2021. doi:10.1039/D1SE00556A. [3] Hien T. T. Nguyen, Dilara Sultanova, Philipp A. Heizmann, Severin Vierrath, and Matthias Breitwieser. Improving the efficiency of fully hydrocarbon-based proton-exchange membrane fuel cells by ionomer content gradients in cathode catalyst layers. Materials Advances, 2022. doi:10.1039/d2ma00761d. [4] Hien Nguyen, Julian Stiegeler, Hannes Liepold, Claudia Schwarz, Severin Vierrath, and Matthias Breitwieser. A comparative study of conditioning methods for hydrocarbon-based proton-exchange membrane fuel cells for improved performance. doi:https://doi.org/10.1002/ente.202300202
Download or read book Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cells written by Jill Elizabeth Newton and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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.
