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Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
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TL;DR: In this paper, three perfluorosulfonic acid membranes (Nafion 120, Nafion 117 and Dow) were characterized by conductivity measurements in the temperature range of 20-90°C and by Small-Angle X-Ray Scattering (SAXS) at room temperature.
140 citations
TL;DR: It is shown that single-layer LDH nanosheets exhibited exceptionally high in-plane conductivities approaching 10−1 S cm−1, which were the highest among anion conductors and comparable to proton conductivities in commercial proton exchange membranes (for example, Nafion).
Abstract: When the dimensionality of layered materials is reduced to the physical limit, an ultimate two-dimensional (2D) anisotropy and/or confinement effect may bring about extraordinary physical and chemical properties. Layered double hydroxides (LDHs), bearing abundant hydroxyl groups covalently bonded within 2D host layers, have been proposed as inorganic anion conductors. However, typical hydroxyl ion conductivities for bulk or lamellar LDHs, generally up to 10-3 S cm-1, are considered not high enough for practical applications. We show that single-layer LDH nanosheets exhibited exceptionally high in-plane conductivities approaching 10-1 S cm-1, which were the highest among anion conductors and comparable to proton conductivities in commercial proton exchange membranes (for example, Nafion). The in-plane conductivities were four to five orders of magnitude higher than the cross-plane or cross-membrane values of restacked LDH nanosheets. This 2D superionic transport characteristic might have great promises in a variety of applications including alkaline fuel cells and water electrolysis.
140 citations
TL;DR: In this paper, the authors compared the electrode kinetic parameters, electrochemically active surface areas, activation energies and reaction orders for the oxygen reduction reaction (ORR) in the sputtered and unsputtered electrodes in proton exchange membrane fuel cells as functions of temperature and pressure.
139 citations
Book•
01 Jan 2009
TL;DR: In this article, the authors present an overview of the history of fuel cells and their application in the field of renewable energy. But they do not discuss the future of fuel cell development.
Abstract: Preface. Symbols. Acronyms and Abbreviations. PART I: INTRODUCTION. Introduction. Chapter 1: The Working Principle of a Fuel Cell. 1.1 Thermodynamic Aspects. 1.2 Schematic Layout of Fuel Cell Units. 1.3 Types of Fuel Cells. 1.4 Layout of a Real Fuel Cell: The Hydrogen-Oxygen Fuel Cell with Liquid Electrolyte. 1.5 Basic Parameters o Fuel Cells. Chapter 2: The Long History o Fuel Cells. 2.1 The Period Prior t 1894. 2.2 The Period from 1894 to 1960. 2.3 The Period from 1960 to the 1990s. 2.4 The Period after the 1990s. PART II: MAJOR TYPES OF FUEL CELLS. Chapter 3: Proton-Exchange Membrane Fuel Cells (PEMFC). 3.1 History of the PEMFC. 3.2 Standard PEMFC Version from the 1990s. 3.3 Special Features of PEMFC Operation. 3.4 Platinum Catalyst Poisoning By Traces of CO in the Hydrogen. 3.5 Commercial Activities in Relation to PEMFC. 3.6 Future Development of PEMFC. 3.7 Elevated-Temperature PEMFC (ET-PEMFC). Chapter 4: Direct Liquid Fuel Cells. Part A: Direct Methanol Fuel Cells. 4.1 Methanol as Fuel for Fuel Cells. 4.2 Current-Producing Reaction and Thermodynamic Parameters. 4.3 Anodic Oxidation of Methanol. 4.4 Milestones in DMFC Development. 4.5 Membrane Penetration by Methanol (Methanol Crossover). 4.6 Varieties of DMFCs. 4.7 Special Operating Features of DMFCs. 4.8 Practical Models of DMFCs and their Features. 4.9 Problems To Be Solved In Future DMFCs. Part B: Direct Liquid Fuel Cells. 4.10 The Problem of Replacing Methanol. 4.11 Fuel Cells Using Organic Liquids as Fuels. 4.12 Fuel Cells Using Inorganic Liquids as Fuels. Chapter 5: Phosphoric Acid Fuel Cells. 5.1 Early Work on Phosphoric Acid Fuel Cells. 5.2 Special Features of Aqueous Phosphoric Acid Solutions. 5.3 Construction of PAFCs. 5.4 Commercial Production of PAFCs. 5.5 Development of Large Stationary Power Plants. 5.6 The Future for PAFCs. 5.7 Importance of PAFCs for Fuel Cell Development. Chapter 6: Alkaline Fuel Cells. 6.1 Hydrogen-Oxygen AFCs. 6.2 Alkaline Hydrazine Fuel Cells. 6.3 Anion-Exchange (Hydroxyl Ion Conducting) Membranes. 6.4 Methanol Fuel Cells with Anion-Exchange Membranes. 6.5 Methanol Fuel Cell with an Invariant Alkaline Electrolyte. Chapter 7: Molten Carbonate Fuel Cells. 7.1 Special Features of High-Temperature Fuel Cells. 7.2 Structure of Hydrogen-Oxygen MCFCs. 7.3 MCFCs with Internal Fuel Reforming. 7.4 Development of MCFC Work. 7.5 The Lifetime of MCFCs. Chapter 8: Solid-Oxide Fuel Cells. 8.1 Schematic Design of Conventional SOFCs. 8.2 Tubular SOFCs. 8.3 Planar SOFCs. 8.4 Monolithic SOFCs. 8.5 Varieties of SOFCs. 8.6 Utilization of Natural Fuels in SOFCs. 8.7 Interim-Temperature SOFCs. 8.8 Low-Temperature SOFCs. 8.9 Factors Influencing the Lifetime of SOFCs. Chapter 9: Other Types of Fuel Cells. 9.1. Redox Flow Cells. 9.2 Biological Fuel Cells. 9.3 Semi-Fuel Cells. 9.4 Direct Carbon Fuel Cells. Chapter 10: Fuel Cells and Electrolysis Processes. 10.1 Water Electrolysis. 10.2 Chlor-Alkali Electrolysis. 10.3 Electrochemical Synthesis Reactions. PART III: INHERENT SCIENTIFIC AND ENGINEERING PROBLEMS. Chapter 11: Fuel Management. 11.1 Reforming of Natural Fuel. 11.2 Production of Hydrogen For Autonomous Power Plants. 11.3 Purification of Technical Hydrogen. 11.4 Hydrogen Transport and Storage. Chapter 12: Electrocatalysis. 12.1 Fundamentals of Electrocatalysis. 12.2 Putting Platinum Catalysts on the Electrodes. 12.3 Supports For Platinum Catalysts. 12.4 Platinum Alloys and Composites as Catalysts for Anodes. 12.5 Non Platinum Catalysts for Fuel Cell Anodes. 12.6 Electrocatalysis of the Oxygen Reduction Reaction. 12.7 The Stability of Electrocatalysts. Chapter 13: Membranes. 13.1 Fuel-Cell-Related Membrane Problems. 13.2 Work to Overcome Degradation of Nafion Membranes. 13.3 Modification of Nafion(r) Membranes. 13.4 Membranes Made From Polymers Without Fluorine. 13.5 Membranes Made from Other Materials. 13.6 Matrix-Type Membranes. 13 7 Membranes with Hydroxyl Ion Conduction . Chapter 14: Small Fuel Cells for Portable Devices. 14.1 Special Operating Features of Mini-Fuel Cells. 14.2 Flat Miniature-Fuel Batteries. 14.3 Silicon-Based Mini-Fuel Cells. 14.4 PCB-Based Mini-Fuel Cells. 14.5 Mini-Solid Oxide Fuel Cells. 14.6 The Problem of Air-Breathing Cathodes. 14.7 Prototypes of Power Units with Mini-Fuel Cells. 14.8 Concluding Remarks. Chapter 15: Mathematical Modeling of Fuel Cells (Felix N. Buchi). 15.1 Zero-Dimensional Models. 15.2 One-Dimensional Models. 15.3 Two Dimensional Models. 15.4 Three Dimensional Models. 15.5 Concluding Remarks . PART IV: COMMERCIALIZATION OF FUEL CELLS. Chapter 16: Applications. 16.1 Large Stationary Power Plants. 16.2 Small Stationary Power Units. 16.3 Fuel Cells for Transport Applications. 16.4 Portables. 16.5 Military Applications. Chapter 17: Fuel Cell Work In Various Countries. 17.1 Driving Forces for Fuel-Cell Work. 17.2 Fuel Cells and the Hydrogen Economy. 17.3 Activities in North America. 17.4 Activities in Europe. 17.5 Activities in Other Countries. 17.6 The Volume of Published Fuel-Cell Work. 17.7 Legislation and Standardization in the Field of Fuel Cells. Chapter 18: Outlook. 18.1 Periods of Alternating Hope and Disappointment Forever? 18.2 Some Misconceptions (Klaus Muller). 18.3 Ideal Fuel Cells. 18.4 Projected Future of Fuel Cells. General Bibliography. Author Index. Subject Index.
139 citations
TL;DR: In this article, single-walled carbon nanotubes (SWCNTs) dispersed with Nafion in a solvent mixture containing de-ionized water and 1-propanol (bisolvent) were sprayed on a poly(ethylene terephthalate) substrate to fabricate flexible transparent conducting films (TCFs).
Abstract: Single-walled carbon nanotubes (SWCNTs) dispersed with Nafion in a solvent mixture containing de-ionized water and 1-propanol (bisolvent) were sprayed on a poly(ethylene terephthalate) substrate to fabricate flexible transparent conducting films (TCFs). Different SWCNT-to-Nafion ratios were used to optimize the film performance of transparence and sheet resistance. The TCFs were then immersed in nitric acid. These steps resulted in p-type doping due to the presence of Nafion in the SWCNT network and de-doping (removal of doping effect) by the acid treatment. X-Ray photoelectron and Raman spectroscopy confirmed that the de-doping effect occurred with the partial removal of Nafion from the nanotube surface by the nitric acid treatment, which improved the film conductivity by a factor of ∼4 with negligible change in transmittance.
139 citations