Perfluorinated membranes

Abstract

Perfluorinated ionomer membranes have been the topic of a tremendous amount of research for over three decades due to their use as the predominant membrane system for proton exchange membrane fuel cell (PEMFC) applications. Their excellent physical properties, including high proton conductivity, oxidative and reductive stability, and mechanical properties, have enabled the PEMFC to reach the levels of performance achieved to date. However, the demands on the fuel cell system are increasing as new applications loom with their needs for lower cost, higher performance, and flexibility to accommodate new fuels. System demands are pushing operating temperatures higher, causing the water balance and humidification of the perfluorinated ionomer membrane to become important issues. This section reviews the status of research and development activities around the Nafion ® perfluorinated ionomer membrane and Nafion ® solutions. The focus of the review is on the measurement of physical property data and new insights into the mechanisms of conduction in these systems. An attempt is made to summarize recent structural studies and characterization techniques that are bringing new insights into the conduction process, as well as recent efforts in mathematical modeling and computer simulations of the conduction process. Finally, membrane‐related issues that arise in the direct methanol PEMFC are reviewed and data on methanol transport in Nafion ® membranes are summarized.

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

“…Although hydrogen is still derived mainly from fossil fuel, energy circulation system with zero pollutant-emission may be accomplished by fuel cell using hydrogen produced from renewable energy sources in the near future. Among the various fuel cell types, proton exchange membrane fuel cells (PEMFCs), also called polymer electrolyte fuel cells (PEFCs) or solid-polymer electrolyte fuel cells (SPEFCs), are a type of fuel cell where proton conductive membranes (i.e., proton exchange membranes (PEMs)) are used as an electrolyte [7,8]. The main advantage of PEMFCs is that they allow for the use of thin polymer electrolytes.…”

Variational Models of Network Formation and Ion Transport: Applications to Perfluorosulfonate Ionomer Membranes

“…Semi-crystalline PFSAs are widely recognized as the benchmark materials in polymer electrolyte membrane fuel cell applications [21,22]. While these polymers inherently possess outstanding chemical and physical properties, the harsh conditions encountered in operating fuel cells and the current demands for long-term durability have revealed that these benchmark materials are susceptible to degradation, particularly in the cast form required to make thin membranes currently in use, as opposed to the thicker extruded version of Nafion.…”

In-situ membrane hydration measurement of proton exchange membrane fuel cells

“…Transport properties such as proton conductivity, gas permeability, water diffusivity, and electro-osmotic drag generally increase with water content [7][8][9][10]. On the other hand, mechanical properties such as modulus, yield stress, tensile strength, fatigue strength, and fracture toughness tend to decrease with increasing water content [6,11,12].…”