Anion Exchange Membrane Fuel Cells (AEMFCs) offer some possible advantages over their Proton Exchange Membrane (PEM) counterparts due to more facile oxygen reduction reaction kinetics (enabling cheaper catalysts), easier water management & balance of plant, cheaper membrane materials, and improved stability of fuel cell stack materials. However, AEMFCs perform significantly worse when exposed to carbon dioxide (CO2), which is present in most applications. Furthermore, because CO2 is so pervasive inside the AEMFC system, its effects are difficult to isolate experimentally. Therefore, a modeling approach was developed which can offer independent control of membrane properties and operating conditions, as well as the contextual freedom to isolate specific aspects of operation. For instance, AEMFCs exhibit a phenomenon known as "self-purging", whereby CO2 is removed from the system during normal operation. Due to self-purging, AEMFCs approach their CO2-free performance as the current density is increased. Without this effect, it would be impractical to use AEMFCs. Despite its importance, the mechanism behind the self-purging phenomenon is still relatively obscure, which makes it difficult to design these devices with this effect in mind. In this modeling approach, existing ex situ AEM models are built up to include operating effects such as current density and gas stream conditions. A morphology model is also developed to investigate the effects of CO2 on electrospun AEMs, which are a class of AEMs with unique morphologies. Finally, we present a study that implements and evaluates the two leading explanations for self-purging, and discuss their relative merits.

This book provides a review of the latest advances in anion exchange membrane fuel cells. Starting with an introduction to the field, it then examines the chemistry and catalysis involved in this energy technology. It also includes an introduction to the mathematical modelling of these fuel cells before discussing the system design and performance of real-world systems. Anion exchange membrane fuel cells are an emerging energy technology that has the potential to overcome many of the obstacles of proton exchange membrane fuel cells in terms of the cost, stability, and durability of materials. The book is an essential reference resource for professionals, researchers, and policymakers around the globe working in academia, industry, and government.

The papers included in this issue of ECS Transactions were originally presented in the symposium ¿Alkaline Electrochemistry in Fuel Cells¿, held during the 216th meeting of The Electrochemical Society, in Vienna, Austria from October 4 to 9, 2009.

Alkaline Anion Exchange Membranes for Fuel Cells Build the fuel cells of the future with this cutting-edge material Alkaline anion exchange membranes (AAEMs) are cutting-edge polyelectrolyte materials with growing renewable energy applications including fuel cells, batteries, hydrogen electrolyzers and electrodialysis technologies. Their use in relatively new alkaline exchange membrane fuel cells (AEMFCs) is designed to produce cost-effective clean energy (electricity) produced by a chemical reaction. Rigorous studies are being conducted to meet the requirements of AAEMs precisely tailored for high anion conductivity and durability for future high energy efficient devices. Hence, over the past few years the academic and industrial scientific communities have explored various polymeric, composite and inorganic materials and studied their properties as a potential AAEM. The accumulated literature in this area of investigation is vast and in order to provide the community with the tools needed to strive forward, there is a clear need to condense this information in a single volume. Alkaline Anion Exchange Membranes for Fuel Cells meets this need with a comprehensive overview of the properties of these membranes and their applications. The book considers recent developments, common challenges, and the long-term prospects for this field of research and engineering. It constitutes a one-stop resource for the development and production of AAEM fuel cells and related electrochemical applications. Alkaline Anion Exchange Membranes for Fuel Cells readers will find: Discussion of electrochemical applications like redox flow batteries, water electrolysis, and many more Detailed treatment of specially tailored cationic groups such as quaternary ammonium and guanidinium Expert advice on efficient fabrication and electrode assembly Alkaline Anion Exchange Membranes for Fuel Cells is ideal for electrochemists, materials scientists, polymer chemists, electrical engineers, and anyone working in power technology or related fields.

Alkaline Anion Exchange Membranes for Fuel Cells Build the fuel cells of the future with this cutting-edge material Alkaline anion exchange membranes (AAEMs) are cutting-edge polyelectrolyte materials with growing renewable energy applications including fuel cells, batteries, hydrogen electrolyzers and electrodialysis technologies. Their use in relatively new alkaline exchange membrane fuel cells (AEMFCs) is designed to produce cost-effective clean energy (electricity) produced by a chemical reaction. Rigorous studies are being conducted to meet the requirements of AAEMs precisely tailored for high anion conductivity and durability for future high energy efficient devices. Hence, over the past few years the academic and industrial scientific communities have explored various polymeric, composite and inorganic materials and studied their properties as a potential AAEM. The accumulated literature in this area of investigation is vast and in order to provide the community with the tools needed to strive forward, there is a clear need to condense this information in a single volume. Alkaline Anion Exchange Membranes for Fuel Cells meets this need with a comprehensive overview of the properties of these membranes and their applications. The book considers recent developments, common challenges, and the long-term prospects for this field of research and engineering. It constitutes a one-stop resource for the development and production of AAEM fuel cells and related electrochemical applications. Alkaline Anion Exchange Membranes for Fuel Cells readers will find: Discussion of electrochemical applications like redox flow batteries, water electrolysis, and many more Detailed treatment of specially tailored cationic groups such as quaternary ammonium and guanidinium Expert advice on efficient fabrication and electrode assembly Alkaline Anion Exchange Membranes for Fuel Cells is ideal for electrochemists, materials scientists, polymer chemists, electrical engineers, and anyone working in power technology or related fields.

High energy density portable power solutions have been of utmost importance for the advancement of modern day necessities such as data and voice communication, vehicular transportation, distributed power generation and storage of energy produced by sustainable power sources. Progress made in fuel cell and lithium-ion battery technologies over the past decade have opened opportunities to power electric and hybrid electric vehicles for long distance transportation. Alkaline membrane fuel cells (AEMFCs) are the new alternatives to proton exchange membrane fuel cells (PEMFCs), which require generous amounts of noble metal-based catalysts on their electrodes. Facile electrode kinetics on non-precious group metal catalysts in alkaline environments is the key factor which has promoted AEMFCs over PEMFCs. While the research on AEMFCs is vastly expanding, high energy density batteries are praiseworthy considering the high cost of hydrogen fuel. The state-of-the-art Li-ion batteries cannot reach the desirable capacity density to power electric vehicles capable of >300 miles on a single charge whereas Li-O2 batteries with a theoretical capacity more than ten times larger than that of Li-ion have become very promising for this application. Chapter 1 of this thesis provides a discussion of the background behind the fuel cell and battery technologies beyond Li-ion along with the electrochemical and analytical techniques employed throughout this investigation. The major deterrent to AEMFC technology is its performance decrease by means of carbonate exchange of the membrane when exposed to carbon dioxide. The second Chapter deals with a quantitative determination of the influence of carbonate ions in the alkaline membrane on interfacial electrode reactions and reactant transport through the membrane. A Pt microelectrode investigation conducted on a commercial anion exchange membrane (AEM) (Tokuyama, A201) showed rather close kinetics for oxygen reduction reaction (ORR) with and without carbonate exchange as well as with a perfluorinated proton exchange membrane analog such as Nafion®. Resolution of the mass transport into constituent components (diffusion coefficient and solubility) showed that the oxygen diffusion coefficient in the AEM exchanged with carbonate ions (CO32−) is lowered while the solubility remained unaffected. These results show remarkable agreement with polarization corrected fuel cell data, thus enabling a method to better resolve interfacial performance of an AEM fuel cell. We have also investigated the kinetics of hydrogen oxidation reaction (HOR) and methanol oxidation reaction (MOR) at the Tokuyama (A201/A901) anion exchange membrane /Pt microelectrode interfaces using solid state electrochemical cells. Diffusion of hydrogen molecules through the membrane was not influenced by the carbonate ions due to the smaller size of the gaseous molecule. However, hydrogen concentration in the anion exchange membrane is low in the presence of carbonate ions. Methanol diffusion is facilitated in the anion exchange polymer electrolyte due to its high water content. A change of the diffusion path length in carbonate polymer electrolytes caused methanol permeability to drop significantly. The kinetic parameters obtained for the AEM in the carbonate form suggests that both hydrogen and methanol oxidation reactions proceed through the carbonate pathway. Therefore, the kinetic parameters obtained are significantly lower than what were observed at the AEM in the hydroxide form. In the third Chapter I demonstrate that a microelectrode can be used as a diagnostic tool to determine O2 transport properties and redox kinetics in dimethyl sulfoxide (DMSO)–based electrolytes for non-aqueous Li-air batteries, and to elucidate the influence of ion-conducting salts on the O2 reduction reaction mechanism. Oxygen reduction/evolution reactions on a carbon microelectrode have been studied in dimethyl sulfoxide-based electrolytes containing Li+ and tetrabutylammonium ((C4H9)4N+) ions. Analysis of chronoamperometric current-time transients of the oxygen reduction reactions in the series of tetrabutylammmonium (TBA) salt-containing electrolytes of TBAPF6, TBAClO4, TBACF3SO3, or TBAN(CF3SO2)2 in DMSO revealed that the anion of the salt exerts little influence on O2 transport. Whereas steady-state ORR currents (with sigmoidal-shaped current-potential curves) were observed in TBA-based electrolytes, peak-shaped current-voltage profiles were seen in the electrolytes containing their Li salt counterparts. The latter response results from the combined effects of the electrostatic repulsion of the superoxide (O2−-) intermediate as it is reduced further to peroxide (O22−) low potentials and the formation of passivation films of the O2 reduction products at the electrode. Raman spectroscopic data confirmed the formation of non-conducting Li2O2 and Li2O on the electrode surface at different reduction potentials in Li salt solutions. Out of the four lithium salt-containing electrolytes studied, namely LiPF6, LiClO4, LiCF3SO3, or LiN(CF3SO2)2 in DMSO, the LiCF3SO3/DMSO solution revealed the most favorable ORR kinetics and the least passivation of the electrode by ORR products. The influence of lithium salts on O2 reduction reactions (ORR) in 1, 2-dimethoxyethane (DME) and tetraethylene glycol dimethyl ether (TEGDME) has been investigated in Chapter 4. Microelectrode studies in a series of tetrabutylammonium salt (TBA salt)/DME-based electrolytes showed that O2 solubility and diffusion coefficient are not significantly affected by the electrolyte anion. The ORR voltammograms on microelectrodes in these electrolytes exhibited steady-state limiting current behavior. In contrast, peak-shaped voltammograms were observed in Li+-conducting electrolytes suggesting a reduction of the effective electrode area by passivating ORR products as well as migration-diffusion control of the reactants at the microelectrode as observed in DMSO-based electrolytes. FT-IR spectra have revealed that Li+ ions are solvated to form solvent separated ion pairs of the type Li+(DME)nPF6− and Li+(TEGDME)PF6− in LiPF6-based electrolytes. On the other hand, the contact ion pairs (DME)mLi+(CF3SO3−) and (TEGDME)Li+(CF3SO3−) appear to form in LiSO3CF3-ontaining electrolytes. In the LiSO3CF3-based electrolytes, the initial ORR product, superoxide (O2−), is stabilized in solution by forming [(DME)m−1(O2−)]Li+(CF3SO3−) and [(TEGDME)(O2−)]Li+(CF3SO3−) complexes. These soluble superoxide complexes are able to diffuse away from the electrode surface reaction sites to the bulk electrolyte in the electrode pores where they decompose to form Li2O2. This explains the higher capacity obtained in Li/O2 cells utilizing LiCF3SO3/TEGDME electrolytes. In Chapter 5 the synthesis of iron(II) phathlaocyanine (FePC)-based catalysts is presented. FePC embedded in a carbon support was heat-treated at a series of temperatures (300oC, 600oC and 800oC) and characterized by means of several spectroscopic and electrochemical techniques. Catalytic oxygen reduction recorded in the low Donor Number acetonitrile (MeCN)-based electrolytes have shown that the oxygen reduction reaction (ORR) mechanism is modified at the catalyst surface. Redox electrochemistry of FePC recorded in argon saturated electrolytes has confirmed that the iron is in the Fe(I) state at the O2 reduction potential in these electrolytes which is capable of stabilizing the superoxide leading to an inner[nil]Helmholtz plane electron transfer reaction. In high Donor Number DMSO[nil]based electrolytes the ORR was not influenced by the catalyst and this has been attributed to the oxidation state of iron being Fe(II) at the superoxide forming potential. The superoxide formed in such conditions are stabilized by the DMSO solvated softer Lewis acid Li+ as the Li+(DMSO)n-O2− ion pair in solution. The ORR reaction in this electrolyte proceeds through an outer Helmholtz plane electron transfer process despite the presence of the FePC catalyst in the electrode. Catalyzed carbon electrodes treated at 300 and 600oC were successfully employed in the low Donor Number tetra ethylene glycol dimethyl ether (TEGDME)[nil]based electrolyte-containing Li-O2

The Encyclopedia of Electrochemical Power Sources, Second Edition, is a comprehensive seven-volume set that serves as a vital interdisciplinary reference for those working with batteries, fuel cells, electrolyzers, supercapacitors, and photo-electrochemical cells. With an increased focus on the environmental and economic impacts of electrochemical power sources, this work not only consolidates extensive coverage of the field but also serves as a gateway to the latest literature for professionals and students alike. The field of electrochemical power sources has experienced significant growth and development since the first edition was published in 2009. This is reflected in the exponential growth of the battery market, the improvement of many conventional systems, and the introduction of new systems and technologies. This completely revised second edition captures these advancements, providing updates on all scientific, technical, and economic developments over the past decade. Thematically arranged, this edition delves into crucial areas such as batteries, fuel cells, electrolyzers, supercapacitors, and photo-electrochemical cells. It explores challenges and advancements in electrode and electrolyte materials, structural design, optimization, application of novel materials, and performance analysis. This comprehensive resource, with its focus on the future of electrochemical power sources, is an essential tool for navigating this rapidly evolving field. - Covers the main types of power sources, including their operating principles, systems, materials, and applications - Serves as a primary source of information for electrochemists, materials scientists, energy technologists, and engineers - Incorporates 365 articles, with timely coverage of environmental and sustainability aspects - Arranged thematically to facilitate easy navigation of topics and easy exploration of the field across its key branches - Follows a consistent structure and features elements such as key objective boxes, summaries, figures, references, and cross-references etc., to help students, faculty, and professionals alike

PEM Fuel Cell Failure Mode Analysis presents a systematic analysis of PEM fuel cell durability and failure modes. It provides readers with a fundamental understanding of insufficient fuel cell durability, identification of failure modes and failure mechanisms of PEM fuel cells, fuel cell component degradation testing, and mitigation strategies against degradation. The first several chapters of the book examine the degradation of various fuel cell components, including degradation mechanisms, the effects of operating conditions, mitigation strategies, and testing protocols. The book then discusses the effects of different contamination sources on the degradation of fuel cell components and explores the relationship between external environment and the degradation of fuel cell components and systems. It also reviews the correlation between operational mode, such as start-up and shut-down, and the degradation of fuel cell components and systems. The last chapter explains how the design of fuel cell hardware relates to failure modes. Written by international scientists active in PEM fuel cell research, this volume is enriched with practical information on various failure modes analysis for diagnosing cell performance and identifying failure modes of degradation. This in turn helps in the development of mitigation strategies and the increasing commercialization of PEM fuel cells.

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.

The book is engineering oriented and covers a large variety of topics ranging from fundamental principles to performance evaluation and applications. It is written systematically and completely on the subject with a summary of state-of-the-art fuel cell technology, filling the need for a timely resource. This is a unique book serving academic researchers, engineers, as well as people working in the fuel cell industry. It is also of substantial interest to students, engineers, and scientists in mechanical engineering, chemistry and chemical engineering, electrochemistry, materials science and engineering, power generation and propulsion systems, and automobile engineering.