Polymer Electrolyte Fuel Cell Durability

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).

Polymer Electrolyte Fuel Cell Durability

Author: Felix N. Büchi

Publisher: Springer Science & Business Media

ISBN: 038785536X

Page: 510

View: 364

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.

Modeling and Diagnostics of Polymer Electrolyte Fuel Cells

This volume, presented by leading experts in the field, covers the latest advances in diagnostics and modeling of polymer electrolyte fuel cells, from understanding catalyst layer durability to start-up under freezing conditions.

Modeling and Diagnostics of Polymer Electrolyte Fuel Cells

Author: Ugur Pasaogullari

Publisher: Springer Science & Business Media

ISBN: 9780387980683

Page: 397

View: 772

This volume, presented by leading experts in the field, covers the latest advances in diagnostics and modeling of polymer electrolyte fuel cells, from understanding catalyst layer durability to start-up under freezing conditions.

Polymer Electrolyte Fuel Cell Degradation

This cutting-edge volume directly addresses the state-of-the-art advances in durability within every fuel cell stack component.

Polymer Electrolyte Fuel Cell Degradation

Author: Matthew M. Mench

Publisher: Academic Press

ISBN: 0123869366

Page: 460

View: 198

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.

Proton Exchange Membrane Fuel Cells 9

The intention of the symposium is to bring together the international community working on the subject and to enable effective interactions between the research and engineering communities. This issue is sold as a two-part set.

Proton Exchange Membrane Fuel Cells 9

Author: T. Fuller

Publisher: The Electrochemical Society

ISBN: 1566777380

Page: 2068

View: 571

This issue of ECS Transactions is devoted to all aspects of research, development, and engineering of proton exchange membrane (PEM) fuel cells and attacks, as well as low-temperature direct-fuel cells. The intention of the symposium is to bring together the international community working on the subject and to enable effective interactions between the research and engineering communities. This issue is sold as a two-part set.

Polymer Electrolyte Fuel Cells 14 PEFC 14

Conclusions The performance and durability effects of the common and BZ were
studied at current densities of 1 and airborne 0.2 A contaminants cm-2. All SO2
contaminants , were found to decrease fuel cell performance significantly and a ...

Polymer Electrolyte Fuel Cells 14  PEFC 14

Author: H. Gasteiger

Publisher: The Electrochemical Society

ISBN: 1607685396

Page: 1247

View: 550

PEM Fuel Cell Durability Handbook Two Volume Set

Analytical approach to polymer electrolyte membrane fuel cell performance and
optimization . Journal of Electroanalytical Chemistry 604 : 72-90 . Gerteisen , D.
and Sadeler , C. 2010. Stability and performance improvement of a PEM fuel cell
 ...

PEM Fuel Cell Durability Handbook  Two Volume Set

Author: Haijiang Wang

Publisher: CRC Press

ISBN: 1439863164

Page: 952

View: 867

While PEM fuel cells are highly efficient, environmentally friendly sources of power, their durability hinders the commercialization of this technology. With contributions from international scientists active in PEM fuel cell research, PEM Fuel Cell Durability Handbook, Two-Volume Set provides a comprehensive source of state-of-the-art research in

Proton Exchange Membrane Fuel Cells 6

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.

Proton Exchange Membrane Fuel Cells 6

Author: Thomas Francis Fuller

Publisher: The Electrochemical Society

ISBN: 1566775019

Page: 1365

View: 691

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.

Modeling and Control of the Fuel Supply System in a Polymer Electrolyte Membrane Fuel Cell

Moreover, to enhance fuel savings, this work proposes a novel model-based technique for estimation of hydrogen concentration, which is used as the basis of fuel purging control.

Modeling and Control of the Fuel Supply System in a Polymer Electrolyte Membrane Fuel Cell

Author: Alireza Ebadi Ghajari

Publisher:

ISBN:

Page: 80

View: 376

Prolonging membrane longevity as well as improving fuel economy are essential steps toward utilization of fuel cells in industrial applications. Focusing on polymer electrolyte membrane (PEM) fuel cells, the present work elucidates a systematic approach to deal with cell durability issues, inflicted by membrane pinholes. This includes the model-based control of fuel overpressure, which is defined as the pressure difference between the anode and cathode compartments, at the inlet side of the fuel cell stack. Moreover, to enhance fuel savings, this work proposes a novel model-based technique for estimation of hydrogen concentration, which is used as the basis of fuel purging control. Employing a Ballard 3kW test station equipped with a 9-cell Mk1100 PEM fuel cell, the entire system is modeled using pneumatic variables. The developed model is experimentally validated. Depending on the underlying objective, a relevant system configuration for the PEM fuel cell anode is adopted. These include a flow-through anode, dead-ended anode, and anode with recirculation structures. A model predictive controller (MPC) is deployed to achieve the controller objectives, which include the improvement in control of the system transient response during the load change, reduction of hydrogen emission, and retaining the cell voltage level of a defective cell, by maintaining the fuel overpressure in the desired region. Furthermore, the controller performance is verified experimentally. Using the pressure drop across the fuel cell stack anode, the hydrogen concentration on the anode side is estimated in a hydrogen-nitrogen gas mixture. This pressure drop is correlated to the dynamic viscosity of a gas mixture. The estimation model which is verified experimentally for various scenarios provides a reliable and cost-effective method that can eliminate the use of the hydrogen sensor. This model is then utilized as the basis for controlling the fuel purging. Deploying an MPC based multivariable control strategy, both fuel overpressure and hydrogen concentration are controlled.

Proton Exchange Membrane Fuel Cells 8

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.

Proton Exchange Membrane Fuel Cells 8

Author:

Publisher: The Electrochemical Society

ISBN: 1566776481

Page: 1078

View: 142

Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells

The structure of the catalyst layers (CLs) has a decisive impact on the performance, durability, and cost of polymer electrolyte membrane (PEM) fuel cells - these are the main technical challenges to the commercialization of PEM fuel cells.

Catalyst Layers in Polymer Electrolyte Membrane Fuel Cells

Author: Jian Zhao

Publisher:

ISBN:

Page: 171

View: 300

The structure of the catalyst layers (CLs) has a decisive impact on the performance, durability, and cost of polymer electrolyte membrane (PEM) fuel cells - these are the main technical challenges to the commercialization of PEM fuel cells. The porous CL conventionally consists of carbon-based platinum (Pt/C) and ionomer (Nafion polymer). An ideal CL should maintain the desired structure with sufficient gas diffusion and water removal channels (pores), proton transport media (ionomer), electron travel pathways (catalyst particles), and optimal three-phase boundaries (TPBs) where electrochemical reaction occurs (reaction sites). Practically, the CL is formed during the fabrication process which determines the physical structures, often represented by porosity, mean pore size, pore size distribution (PSD) and specific surface area. The physical structures, in turn, determine the effective transport properties such as effective mass diffusion coefficient and permeability for the reactant in the CLs. However, there is still no clear understanding of what is the optimal structure for the CLs. To investigate the structure of CLs, three aspects are studied in the present thesis work: (i) the effect of fabrication process on the resulting structure, (ii) the effect of the CL structure on its macro-properties, and (iii) the effect of the structure and macro-properties on the mass transport phenomena and the associated cell performance. Many factors including fabrication techniques and CL compositions have a significant impact on the structure formation of CLs. However, how these factors affect the structure is still unclear. Additionally, there lacks experimental characterization of the structure such as porosity, PSD, specific surface area, mean pore size, and surface fractal dimension, as well as mass transport properties such as effective diffusion coefficient and gas permeability for the CLs in literature. With the experimentally determined structural and mass transport parameters of the CLs and the associated electrodes, the mass transport phenomena in PEM fuel cells can be quantitatively analyzed. In the present thesis work, the CL pore structure is experimentally characterized by the method of standard porosimetry (MSP), which is established based on the phenomenon of capillary equilibrium in the wetted porous materials. By the means of MSP, a comprehensive characterization of the structure in terms of porosity, PSD, specific surface area, mean pore size, and surface fractal dimension is obtained. In addition, the effective diffusion coefficient of the CL is studied by the modified Loschmidt Cell, built based on the Fick's law of diffusion. The parameters including effective diffusion coefficient, diffusion resistivity, and its relation with the porosity and mean pore size is investigated. Further, the permeability is measured based on Darcy's law via a custom-engineered apparatus developed in my thesis work. The effect of Pt loading, temperature, flow rate, and gas species is explored in this thesis study. With the experimentally determined pore structure characterization and mass transport properties, a numerical study is performed for the better understanding of the mass transport mechanisms in the porous electrodes. The cell performance conducted in our lab is also reported in the present thesis for a better understanding of the ex-situ experiment and a comparison with the numerical modeling. The experimental and numerical studies presented in the present thesis work is of great significance to (i) understand the structure of the CLs, (ii) to understand the relation between the structure and the mass transport properties such as the effective diffusion coefficient and permeability, and (iii) to understand the effect of the structural parameters and mass transport properties on the mass transport phenomena and hence the cell performance in the PEM fuel cells.

Proton Exchange Membrane Fuel Cells

Materials Properties and Performance David P. Wilkinson, Jiujun Zhang, Rob Hui
, Jeffrey Fergus, Xianguo Li ... The polymer electrolyte fuel cell (PEFC) or proton
exchange membrane fuel cell—also known as the polymer electrolyte ...

Proton Exchange Membrane Fuel Cells

Author: David P. Wilkinson

Publisher: CRC Press

ISBN: 9781439806661

Page: 460

View: 661

A Detailed, Up-to-Date Treatment of Key Developments in PEMFC Materials The potential to revolutionize the way we power our world Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. Written by international PEMFC scientists and engineers from top-level organizations, Proton Exchange Membrane Fuel Cells: Materials Properties and Performance provides a single resource of information for understanding how to select and develop materials for improved PEMFC performance. The book focuses on the major components of the fuel cell unit, along with design and modeling aspects. It covers catalysts and catalyst layers, before discussing the key components of membranes, diffusion layers, and bipolar plates. The book also explores materials modeling for the PEMFC. This volume assesses the current status of PEMFC fuel cell technology, research and development directions, and the scientific and engineering challenges facing the fuel cell community. It demonstrates how the production of a commercially viable PEMFC requires a compromise of materials with adequate properties, design interaction, and manufacturability.

Polymer Electrolyte Membrane and Direct Methanol Fuel Cell Technology

This two volume set reviews the fundamentals, performance, and in situ characterization of PEMFCs and DMFCs.

Polymer Electrolyte Membrane and Direct Methanol Fuel Cell Technology

Author: Christoph Hartnig

Publisher: Elsevier

ISBN: 0857095471

Page: 430

View: 489

Polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) technology are promising forms of low-temperature electrochemical power conversion technologies that operate on hydrogen and methanol respectively. Featuring high electrical efficiency and low operational emissions, they have attracted intense worldwide commercialization research and development efforts. These R&D efforts include a major drive towards improving materials performance, fuel cell operation and durability. In situ characterization is essential to improving performance and extending operational lifetime through providing information necessary to understand how fuel cell materials perform under operational loads. This two volume set reviews the fundamentals, performance, and in situ characterization of PEMFCs and DMFCs. Volume 1 covers the fundamental science and engineering of these low temperature fuel cells, focusing on understanding and improving performance and operation. Part one reviews systems fundamentals, ranging from fuels and fuel processing, to the development of membrane and catalyst materials and technology, and gas diffusion media and flowfields, as well as life cycle aspects and modelling approaches. Part two details performance issues relevant to fuel cell operation and durability, such as catalyst ageing, materials degradation and durability testing, and goes on to review advanced transport simulation approaches, degradation modelling and experimental monitoring techniques. With its international team of expert contributors, Polymer electrolyte membrane and direct methanol fuel cell technology Volumes 1 & 2 is an invaluable reference for low temperature fuel cell designers and manufacturers, as well as materials science and electrochemistry researchers and academics. Covers the fundamental science and engineering of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs), focusing on understanding and improving performance and operation Reviews systems fundamentals, ranging from fuels and fuel processing, to the development of membrane and catalyst materials and technology, and gas diffusion media and flowfields, as well as life cycle aspects and modelling approaches Details performance issues relevant to fuel cell operation and durability, such as catalyst ageing, materials degradation and durability testing, and reviews advanced transport simulation approaches, degradation modelling and experimental monitoring techniques

PEM Fuel Cells

This new edition of Dr. Barbir’s groundbreaking book still lays the groundwork for engineers, technicians and students better than any other resource, covering fundamentals of design, electrochemistry, heat and mass transport, as well as ...

PEM Fuel Cells

Author: Frano Barbir

Publisher: Academic Press

ISBN: 012398372X

Page: 444

View: 847

Demand for fuel cell technology is growing rapidly. Fuel cells are being commercialized to provide power to buildings like hospitals and schools, to replace batteries in portable electronic devices, and as replacements for internal combustion engines in vehicles. PEM (Proton Exchange Membrane) fuel cells are lighter, smaller, and more efficient than other types of fuel cell. As a result, over 80% of fuel cells being produced today are PEM cells. This new edition of Dr. Barbir’s groundbreaking book still lays the groundwork for engineers, technicians and students better than any other resource, covering fundamentals of design, electrochemistry, heat and mass transport, as well as providing the context of system design and applications. Yet it now also provides invaluable information on the latest advances in modeling, diagnostics, materials, and components, along with an updated chapter on the evolving applications areas wherein PEM cells are being deployed. Comprehensive guide covers all aspects of PEM fuel cells, from theory and fundamentals to practical applications Provides solutions to heat and water management problems engineers must face when designing and implementing PEM fuel cells in systems Hundreds of original illustrations, real-life engineering examples, and end-of-chapter problems help clarify, contextualize, and aid understanding

Investigating Cathode Catalyst Layer Degradation in Polymer Electrolyte Fuel Cells by Lab based X ray Computed Tomography

In this thesis, a novel small-scale fuel cell fixture that mimics the performance and degradation features of a full-scale PEFC assembly is presented.

Investigating Cathode Catalyst Layer Degradation in Polymer Electrolyte Fuel Cells by Lab based X ray Computed Tomography

Author: Robin White

Publisher:

ISBN:

Page: 190

View: 865

The commercial viability of polymer electrolyte fuel cells (PEFCs) has increased rapidly over recent years with applications in public and commercial transportation, back-up power, and un-manned autonomous systems. This has come as a direct result toward increasing evidence and severity of climate change due to greenhouse gas emissions; pushing the need for government regulations to introduce stricter limits on fossil fuel combustion in new passenger cars, as well as in other light-to heavy-duty vehicles. Further cost and durability improvements in PEFCs present significant opportunities as the technology continues to be refined. PEFCs are assembled as a series of layers, each having specific functionalities to optimize the cell performance during electrochemical conversion of chemical potential energy, in the way of hydrogen and oxygen, into useable electrical power, heat, and water. These PEFC materials can undergo considerable changes during operation, and lifetime testing through critical degradation processes, which can be uniquely captured using X-ray Computed Tomography (XCT) in this complex multi-layered system. XCT provides a unique ability to delve into the innermost structures through non-destructive imaging in diverse and extensive application areas. In this thesis, a novel small-scale fuel cell fixture that mimics the performance and degradation features of a full-scale PEFC assembly is presented. By combining the 3-dimensional visualization through repeated identical location tomography using XCT scans at various temporal stages of this small-scale fixture, powerful in-situ and operando investigations of dynamic material properties are obtained. This methodology is termed as 4D CT. By means of applying accelerated stress tests focused on cathode catalyst layer degradation, unique insight into the lifetime, dynamics and interactions between the catalyst layer and surrounding components was uniquely obtained using custom developed tools and analysis methods. These new methods allow for new investigations into the temporal changes of water saturation and cathode catalyst layer morphology. It has been found that during ageing, the morphological interaction between different layers can have a considerable impact on degradation mechanisms such as crack propagation. These results uncover unique evidence around the strongly interactive nature of material degradation within a fuel cell that has previously been unobserved.

High Temperature Polymer Electrolyte Membrane Fuel Cells

This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs).

High Temperature Polymer Electrolyte Membrane Fuel Cells

Author: Qingfeng Li

Publisher: Springer

ISBN: 3319170821

Page: 545

View: 652

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.

Fuel Cell Seminar 2007

... and cross-linked membranes were evaluated as polymer electrolyte
membranes for polymer electrolyte fuel cells (PEFCs). ... at 90 oC and 85 %RH
for 1600 h without any reduction in cell performance, indicating their high fuel cell
durability.

Fuel Cell Seminar 2007

Author: M. C. Williams

Publisher: The Electrochemical Society

ISBN: 1566776392

Page: 766

View: 800

There are many fuel cell technologies, entities, commercialization plans, and research and development activities at various states of maturity. The fuel cell efforts encompassed in this issue represents a major, international research and development and demonstration activity. Fuel cells are a topic of great interest and shall probably remain so for some time. The Fuel Cell Seminar and Exposition remains a major social, technical, and marketing forum for fuel cells. The Electrochemical Society, through its collaboration with the Seminar, is able to bring this issue of ECS Transactions, containing important contributions, to a broad technical audience.

Handbook of Fuel Cells

This new two-volume set provides an authoritative and timely guide to these recent developments in fuel cell research.

Handbook of Fuel Cells

Author:

Publisher: John Wiley & Sons

ISBN: 0470723114

Page:

View: 944

Role of Wettability in Fuel Cells

This work is focused on sophisticated schemes for surface wettability impact on fuel cell performance are required by using proper wettability characteristics for the fuel cell components.

Role of Wettability in Fuel Cells

Author: Jaehyung Park

Publisher:

ISBN:

Page:

View: 965

Fuel cells have received significant attention as a promising candidate for efficient and emission-free power in automotive, stationary, and portable applications. This work is focused on sophisticated schemes for surface wettability impact on fuel cell performance are required by using proper wettability characteristics for the fuel cell components. Foreign cations are shown to cause mass transport losses, in particular due to wettability changes in the gas diffusion media (GDM) and have a major impact on the durability and the performance of polymer electrolyte fuel cell (PEFC). The effects of cationic impurities on fuel cell system performance, especially on the water management has been studied by employing in-situ and ex-situ contamination methods. Changes in the wettability of the GDM surface following the in-situ contamination injection were quantified using a force tensiometer employing the Wilhelmy plate method. Identification and mitigation of adverse effects of cationic airborne contaminants on fuel cell system performance and durability has been studied and effective recovery methods are proposed. A new membrane electrode assembly (MEA) concept is introduced, where the carbon paper substrate is eliminated and the entire GDM consists of only the micro-porous layer (MPL) directly applied on the catalyst coated membrane (CCM). Spray deposition with a heated plate is used to fabricate the MPL directly onto both sides of the catalyst coated membrane (CCM), simplifying the fabrication and assembly, and results in a more robust interface between the MPL and the catalyst layer. The new MEA structure provides superior pathways for gas transport and water evacuation, reduces flooding at high current densities, and results in a stable voltage at higher current densities by improving mass transport. Wilhelmy balance in a force tensiometer was successfully applied to study the wetting property of an electrode matrix in the electrolyte of molten carbonate fuel cells (MCFCs). MCFCs are high-temperature fuel cells that use a molten carbonate salt mixture as an electrolyte integrated in a porous ceramic matrix. The performance of MCFC highly depends on the surface tension of the molten carbonate and the contact angle with the electrolyte matrix in the solution. A new formulation based on the Wilhelmy force balance equation is developed to determine the contact angle for samples with irregular shapes.

Proton Conducting Membrane Fuel Cells IV

DURABILITY ISSUES AT THE POLYMER ELECTROLYTE MEMBRANE AND
THE ELECTROCATALYST INTERFACE WITH NON - FLUORINATED
IONOMERS Lei Zhang , Vivek S . Murthy and Sanjeev Mukerjee Department of
Chemistry and ...

Proton Conducting Membrane Fuel Cells IV

Author:

Publisher: The Electrochemical Society

ISBN: 9781566774345

Page: 776

View: 258