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Author : Nicholas William DeLuca
Publisher :
ISBN 13 :
Total Pages : 468 pages
Book Rating : 4.:/5 (213 download)
Download or read book Nafion® Blend Membranes for the Direct Methanol Fuel Cell written by Nicholas William DeLuca and published by . This book was released on 2008 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Bradley Paul Ladewig
Publisher :
ISBN 13 :
Total Pages : 130 pages
Book Rating : 4.:/5 (224 download)
Download or read book Nafion Nanocomposite Membranes for the Direct Methanol Fuel Cell written by Bradley Paul Ladewig and published by . This book was released on 2006 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Bradley Ladewig
Publisher :
ISBN 13 : 9783836497947
Total Pages : 144 pages
Book Rating : 4.4/5 (979 download)
Download or read book Nafion Nanocomposite Membranes for the Direct Methanol Fuel Cell written by Bradley Ladewig and published by . This book was released on 2008-04-01 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct methanol fuel cells are seen as an attractive potential replacement for lithium ion batteries in small portable electronic devices. Crucial to the operation of direct methanol fuel cells is the proton exchange membrane, which conducts protons from the anode to the cathode, while acting as an insulator to electrons. The proton exchange membrane should also act as a physical barrier to the methanol and water at the anode, and the air or oxygen at the cathode, however the most commonly used proton exchange membrane, Nafion, suffers from significant methanol permeation from the anode to the cathode during operation. This work examined the effect of modifying Nafion membranes through in situ sol gel synthesis of silicon oxide nanoparticles with varying surface chemistry and microstructure. Detailed structural characterisation of the composite structure was undertaken using a wide variety of techniques including small angle X-ray and neutron scattering, wide-angle X-ray scattering, thermal analysis techniques and positron annihilation lifetime spectroscopy. Transport properties of the composite membranes were evaluated by impedance spectroscopy and pervaporation techniques.
Author : Javaid Zaidi
Publisher : Springer Science & Business Media
ISBN 13 : 0387735313
Total Pages : 439 pages
Book Rating : 4.3/5 (877 download)
Download or read book Polymer Membranes for Fuel Cells written by Javaid Zaidi and published by Springer Science & Business Media. This book was released on 2008-10-27 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the late-1960’s, perfluorosulfonic acid (PFSAs) ionomers have dominated the PEM fuel cell industry as the membrane material of choice. The “gold standard’ amongst the many variations that exist today has been, and to a great extent still is, DuPont’s Nafion® family of materials. However, there is significant concern in the industry that these materials will not meet the cost, performance, and durability requirementsnecessary to drive commercialization in key market segments – es- cially automotive. Indeed, Honda has already put fuel cell vehicles in the hands of real end users that have home-grown fuel cell stack technology incorporating hydrocarbon-based ionomers. “Polymer Membranes in Fuel Cells” takes an in-depth look at the new chem- tries and membrane technologies that have been developed over the years to address the concerns associated with the materials currently in use. Unlike the PFSAs, which were originally developed for the chlor-alkali industry, the more recent hydrocarbon and composite materials have been developed to meet the specific requirements of PEM Fuel Cells. Having said this, most of the work has been based on derivatives of known polymers, such as poly(ether-ether ketones), to ensure that the critical requirement of low cost is met. More aggressive operational requi- ments have also spurred the development on new materials; for example, the need for operation at higher temperature under low relative humidity has spawned the creation of a plethora of new polymers with potential application in PEM Fuel Cells.
Author : Klaus-Viktor Peinemann
Publisher : John Wiley & Sons
ISBN 13 : 3527622241
Total Pages : 304 pages
Book Rating : 4.5/5 (276 download)
Download or read book Membranes for Energy Conversion written by Klaus-Viktor Peinemann and published by John Wiley & Sons. This book was released on 2008-09-08 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on recent developments in innovative energy conversion, this second volume features emerging applications with the capacity to transform the entire energy economy. Specific examples include the development of sulfonated polyarylether-type polymers as proton exchange membranes for high- and medium-temperature polymer electrode fuel cells (PEFC), with an entire section devoted to the rapidly expanding field of materials development for solid oxide fuel cells (SOFC). The result is a detailed and invaluable source of information for those involved in the chemical, material science and engineering fields of power generation.
Author : Chaiwat Yoonoo
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (711 download)
Download or read book Development of Nafion-mordenite Composite Membranes for Direct Methanol Fuel Cell Application written by Chaiwat Yoonoo and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Jairo Ivan Garnica Rodríguez
Publisher :
ISBN 13 :
Total Pages : 89 pages
Book Rating : 4.:/5 (682 download)
Download or read book Polyaniline-silica-nafion Composite Membranes for Direct Methanol Fuel Cells written by Jairo Ivan Garnica Rodríguez and published by . This book was released on 2005 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Hongze Luo
Publisher :
ISBN 13 :
Total Pages : 240 pages
Book Rating : 4.:/5 (629 download)
Download or read book Polymer/nano-organic Composite Proton Exchange Membranes for Direct Methanol Fuel Cell Application written by Hongze Luo and published by . This book was released on 2005 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proton exchange membrane is one key component of direct methanol fuel cells, which has double functions of conducting protons, separating fuels and oxidant. At present, the performance and price of sulfonic acid proton exchange membrane used in direct methanol fuel cells are deeply concerned. In order to reduce membrane 's cost and improve performance of Nafion membrane, three different kinds of membranes have been studied in this thesis. These membranes are SPEEK membranes, SPEEK/ZP composite membranes and Nafion/ZP composite membranes.
Author : Surbhi Sharma
Publisher : Walter de Gruyter GmbH & Co KG
ISBN 13 : 311064732X
Total Pages : 172 pages
Book Rating : 4.1/5 (16 download)
Download or read book Membranes for Low Temperature Fuel Cells written by Surbhi Sharma and published by Walter de Gruyter GmbH & Co KG. This book was released on 2019-06-04 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membranes for Low Temperature Fuel Cells provides a comprehensive review of novel and state-of-the-art polymer electrolyte membrane fuel cells (PEMFC) membranes. The author highlights requirements and considerations for a membrane as an integral part of PEMFC and its interactions with other components. It is an indispensible resource for anyone interested in new PEMFC membrane materials and concerned with the development, optimisation and testing of such membranes. Various composite membranes (polymer and non-polymer) are discussed along with analyses of the latest fi ller materials like graphene, ionic liquids, polymeric ionic liquids, nanostructured metal oxides and membrane concepts unfolding in the field of PEMFC. This book provides the latest academic and technical developments in PEMFC membranes with thorough insights into various preparation, characterisation, and testing methods utilised. Factors affecting proton conduction, water adsorption, and transportation behaviour of membranes are also deliberated upon. Provides the latest academic and technical developments in PEMFC membranes. Reviews recent literature on ex situ studies and in situ single-cell and stack tests investigating the durability (chemical, thermomechanical) and degradation of membranes. Surbhi Sharma, MSc, PhD Working on graphene oxide and fuel cells since 2007, she has published about 50 research articles/book chapters and holds a patent. She has also been awarded various research grants.
Author : Bo Yang (Ph. D.)
Publisher :
ISBN 13 :
Total Pages : 364 pages
Book Rating : 4.:/5 (98 download)
Download or read book Development of New Membranes for Proton Exchange Membrane and Direct Methanol Fuel Cells written by Bo Yang (Ph. D.) and published by . This book was released on 2004 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) are drawing much attention as alternative power sources for transportation, stationary, and portable applications. Nafion membranes are presently used in both PEMFC and DMFC as electrolytes, but are confronted with a few difficulties: (i) high cost, (ii) limited operating temperature of 100 °C, and (iii) high methanol permeability. With an aim to overcome some of the problems encountered with the Nafion membranes, this dissertation focuses on the design and development of a few materials systems for use in PEMFC and/or DMFC. The incorporation of hydrous Ta2O5·nH2O into Nafion membrane as well as the electrodes is shown to help the cell to retain water to higher temperatures. Membrane-electrode assembly (MEA) consisting of the composite membrane shows better cell performance at 100 and 110 °C than that with plain Nafion membrane, and a high power density of ~ 650 mW/cm2 at 100 °C is obtained with H2 - CO mixture as the fuel due to a significant alleviation of the CO poisoning of the catalysts. Sulfonated poly(etheretherketone) (SPEEK) membranes with various sulfonation levels are prepared and investigated in DMFC. With a sulfonation level of ~ 50 %, the SPEEK membranes exhibit low methanol permeability and electrochemical performance comparable to that of Nafion at around 60 °C, making it an attractive low-cost alternative to Nafion. From a comparative study of the structural evolutions with temperature in 2 M methanol solution, it is found that the lower methanol permeability of SPEEK membranes is related to the less connected and narrower pathways for water/methanol permeation. The dry proton conductor CsHSO4 shows a high proton conductivity of ~ 10−3 S/cm at temperatures 140 °C and water is not needed for proton conduction. However, it is found that CsHSO4 decomposes to Cs2SO4 and H2S at 150 °C in H2 atmosphere in contact with the Pt/C catalyst. Thus, new catalyst materials need to be explored for CsHSO4 to be used in practical high temperature PEMFC. Thin self-humidifying Nafion membranes with dispersed Pt/C catalyst powder are prepared and tested in PEMFC with dry H2 and O2. The Pt/C particles provide sites for catalytic recombination of H2 and O2 permeating from the anode and cathode, and the water produced at these sites directly humidifies the membrane. The performance of the cell with the self-humidifying membrane operated with dry reactants is ~ 90 % of that obtained with well humidified H2 and O2.
Author : Jun Zhu
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (81 download)
Download or read book Development of Polypyrrole/nafion Composite Membranes and a Dynamic Hydrogen Reference Electrode for Direct Methanol Fuel Cells written by Jun Zhu and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Brett Libby
Publisher :
ISBN 13 :
Total Pages : 550 pages
Book Rating : 4.:/5 (319 download)
Download or read book Improving Selectivity in Methanol Fuel Cell Membranes written by Brett Libby and published by . This book was released on 2001 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Sossina M. Haile
Publisher :
ISBN 13 :
Total Pages : 30 pages
Book Rating : 4.:/5 (318 download)
Download or read book Novel Composite Membranes for Fuel Cells written by Sossina M. Haile and published by . This book was released on 2003 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Wen Li
Publisher :
ISBN 13 :
Total Pages : 304 pages
Book Rating : 4.:/5 (457 download)
Download or read book Development and Understanding of New Membranes Based on Aromatic Polymers and Heterocycles for Fuel Cells written by Wen Li and published by . This book was released on 2009 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct methanol fuel cells (DMFC) are appealing as a power source for portable devices as they do not require recharging with an electrical outlet. However, the DMFC technology is confronted with the high crossover of methanol fuel from the anode to the cathode through the currently used Nafion membrane, which not only wastes the fuel but also poisons the cathode platinum catalyst. With an aim to overcome the problems encountered with the Nafion membrane, this dissertation focuses on the design and development of new polymeric membrane materials for DMFC and a fundamental understanding of their structure-property-performance relationships. Several polymeric blend membranes based on acid-base interactions between an aromatic acidic polymer such as sulfonated ploy(ether ether ketone) (SPEEK) and an aromatic basic polymer such as heterocycle tethered poly(sulfone) (PSf) have been explored. Various heterochylces like nitro-benzimidazole (NBIm), 1H-Perimidine (PImd), and 5-amino-benzotriazole (BTraz) have been tethered to PSf to understand the influence of pKa values and the size of the hetrocycles. The blend membranes show lower methanol crossover and better performance in DMFC than plain SPEEK due to an enhancement in proton conductivity through acid-base interactions and an insertion of the heterocycle side groups into the ionic clusters of SPEEK as indicated by small angle Xray scattering and TEM data. The SPEEK/PSf-PImd blend membrane shows the lowest methanol crossover due to the larger size of the side groups, while the SPEEK/PSf-BTraz blend membrane shows the highest proton conductivity and maximum power density. To further investigate the methanol-blocking effect of the heterocycles, N, N'-Bis- (1H-benzimidazol-2-yl)-isophthalamide (BBImIP) having two amino-benzimidazole groups bonded to a phenyl ring has been incorporated into sulfonated polysulfone (SPSf) and SPEEK membranes. With two 2-amino-benzimidazole groups, which could greatly increase the proton transfer sites, and three phenyl rings, which are compatible with the aromatic polymers, the BBImIP/SPSf and BBImIP/SPEEK blend membranes show suppressed methanol crossover and increased fuel cell performance in DMFC. Novel sulfonated copolymers based on poly(aryl ether sulfone) (SPS-DP) that exhibit low methanol crossover have been synthesized and explored as a methanol-barrier center layer in a multilayer membrane configuration having SPEEK as the outer layers. These multilayer membranes exhibit better performance in DMFC than plain SPEEK and Nafion 115 membranes due to suppressed methanol crossover. To address the issue of incompatibility between the new hydrocarbon-based membranes synthesized and the Nafion ionomer used in the catalyst layer in fabricating membrane-electrode assemblies (MEAs), the MEAs have been fabricated with the SPEEK membranes and 10 to 30 % SPEEK ionomer in the catalyst layer. These MEAs exhibit better performance in DMFC compared to the MEAs fabricated with the SPEEK membranes and Nafion ionomer in the catalyst layer due to lower interfacial resistance.
Download or read book למה לחתולה אין חברים? written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 19 pages
Book Rating : 4.:/5 (742 download)
Download or read book Polyphosphazene-Based Proton-Exchange Membranes for Direct Liquid Methanol Fuel Cells written by and published by . This book was released on 2005 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton-exchange membranes for direct methanol fuel cells were prepared from sulfonated poly[bis(3-methylphenoxy)phosphazene] and sulfonated poly[bis(phenoxy)phosphazene]. The methylphenoxy polymer was blended with Kynar Flex and solution cast into thin films, whereas the bisphenoxy material was blended with polybenzimidazole (for acid-base complexation crosslinking) prior to membrane casting. Some of the films containing poly[bis(3- methylphenoxy)phosphazene] were UV-crosslinked for added control of swelling and methanol permeability. For most membranes, the proton conductivity was sufficiently high for direct methanol fuel cell (DMFC) applications but the methanol permeability was significantly lower than that in DuPont's Nafion. Membranes composed of sulfonated poly[bis(phenoxy)phosphazene] (SPOP) and polybenzimidazole (PBI) worked particularly well in a DMFC (at 60 degrees C 1.0 M methanol, and ambient pressure air). Membrane performance in a DMFC was dependent on the blend composition (ion-exchange capacity of SPOP and wt% of added PBI). For an 82 m thick membrane composed of 1.2 mmol/g IEC SPOP with 3 wt% PBI, the maximum power density was 89 mW/cm2 (versus 96 mW/cm2 with Nafion 117), while the methanol crossover was 2.6 times lower than that with Nafion 117.
Author : Chetan Vasant Mahajan
Publisher :
ISBN 13 :
Total Pages : 342 pages
Book Rating : 4.:/5 (869 download)
Download or read book Atomistic and Molecular Simulations of Novel Acid-base Blend Membranes for Direct Methanol Fuel Cells written by Chetan Vasant Mahajan and published by . This book was released on 2013 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the main challenges to transform highly useful Direct Methanol Fuel Cells (DMFC) into a commercially viable technology has been to develop a low cost polymer electrolyte membrane (PEM) with high proton conductivity, high stability and low methanol crossover under operating conditions desirably including high temperatures. Nafion, the widely used PEM, fails to meet all of these criteria simultaneously. Recently developed acid-base polymer blend membranes constitute a promising class of PEMs alternative to Nafion on above criteria. Even though some of these membranes produce better performance than Nafion, they still present numerous opportunities for maximizing high temperature proton conductivity and dimensional stability with concomitant minimization of methanol crossover. Our contribution embarks on the fundamental study of one such novel class of blend membranes viz., sulfonated poly (ether ether ketone) (SPEEK)(95 % by weight) blended with polysulfone tethered with base (5 % by weight) such as 2-aminobenzimidazole (ABIm), 5-amino-benzotriazole (BTraz) and 1H-perimidine (PImd), developed by Manthiram group at The University of Texas at Austin. In this work, we report extensive all-atom classical as well as ab-initio molecular dynamics (MD) simulations of such water-methanol solvated blend membranes (as well as pure SPEEK and Nafion) the first time. Our approach consists of three steps: (1) Predict dynamical properties such as diffusivities of water, methanol and proton in such membranes (2) Validate against experiments (3) Develop understanding on the interplay between basic chemistry, structure and properties, the knowledge that can potentially be used to develop better candidate membranes. In particular, we elucidate the impact of simple, fundamental physiochemical features of the polymeric membranes such as hydrophilicity, hydrophobicity, structure or the size of the base on the structural manifestations on the bigger scale such as nanophase segregation, hydrogen bonding or pore sizes, which ultimately affect the permeant transport through such systems.
