Topic
Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: A polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications and extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-basedPEMFC systems.
Abstract: Proton exchange membrane fuel cells (PEMFCs) are promising devices for clean power generation in automotive, stationary, and portable applications. Perfluorosulfonic acid (PFSA) ionomers (for example, Nafion) have been the benchmark PEMs; however, several problems, including high gas permeability, low thermal stability, high production cost, and environmental incompatibility, limit the widespread dissemination of PEMFCs. It is believed that fluorine-free PEMs can potentially address all of these issues; however, none of these membranes have simultaneously met the criteria for both high performance (for example, proton conductivity) and durability (for example, mechanical and chemical stability). We present a polyphenylene-based PEM (SPP-QP) that fulfills the required properties for fuel cell applications. The newly designed PEM exhibits very high proton conductivity, excellent membrane flexibility, low gas permeability, and extremely high stability, with negligible degradation even under accelerated degradation conditions, which has never been achieved with existing fluorine-free PEMs. The polyphenylene PEM also exhibits reasonably high fuel cell performance, with excellent durability under practical conditions. This new PEM extends the limits of existing fluorine-free proton-conductive materials and will help to realize the next generation of PEMFCs via cost reduction as well as the performance improvement compared to the present PFSA-based PEMFC systems.
155 citations
TL;DR: Chitosan membranes crosslinked in sulfuric acid are evaluated for their thermal stability, water absorption and proton conductivity properties as alternative proton exchange membrane (PEM) material for application in fuel cells.
155 citations
TL;DR: Two methods for restoring lost capacity are developed, thereby enabling long-term operation of VRBs to be achieved without the substantial loss of energy resulting from periodic total remixing of electrolytes.
Abstract: We will show two new methods to restore capacity during the long term charge-discharge cycling and operation
155 citations
TL;DR: In this article, an accelerated degradation test of selected membranes was carried out to determine their stability in the fully charged positive electrolyte solution of the vanadium redox battery, where each membrane was soaked in both 1.0 and 0.1 M V(V) solutions for extended periods of time and UV-visible spectroscopy was used to determine the rate of oxidation of the membrane by V (V) to produce V(IV) ions in solution.
Abstract: Accelerated degradation tests of selected membranes were carried out to determine their stability in the fully charged positive electrolyte solution of the vanadium redox battery. Each membrane was soaked in both 1.0 and 0.1 M V(V) solutions for extended periods of time and UV–visible spectroscopy was used to determine the rate of oxidation of the membrane by V(V) to produce V(IV) ions in solution. The membranes were then evaluated for any changes in their resistance, IEC, diffusivity and water transfer properties. FESEM was used to analyse the membranes for physical damage. Different trends were observed in the 1.0 and 0.1 M V(V) electrolytes. Of the membranes studied, Nafion 112E/H+ showed the worst stability in the 0.1 M V(V) solution but one of the best stabilities in 1.0 M V(V). The dilute V(V) electrolyte appears to enter the pores of the membrane more readily as the membranes swell significantly in this solution. The 0.1 M V(V) solution therefore causes accelerated deterioration of the membrane performance as a result of physical destruction, chemical modification or a combination of both. The effect is more pronounced in the membranes that have a higher degree of swelling in the vanadium electrolyte.
155 citations
TL;DR: The most widely used polymer membrane for direct alcohol fuel cells (DAFCs) is Nafion because it exhibits superior proton conductivity and excellent mechanical properties and chemical stability as discussed by the authors.
Abstract: Direct alcohol fuel cells (DAFCs) have attracted considerable attention recently as alternative energy resources due to their high efficiency compared with other types of fuel cells. Currently, the two most common types of DAFCs are direct methanol fuel cells (DMFCs) and direct ethanol fuel cells (DEFCs), which use methanol and ethanol solutions as fuel, respectively. The most widely used polymer membrane for DAFCs is Nafion because it exhibits superior proton conductivity and excellent mechanical properties and chemical stability. However, Nafion membranes for DAFCs are expensive, have limited device lifetimes due to chemical and mechanical degradation, and have higher fuel crossovers through the membrane. Typically, to improve Nafion membranes, many researchers have modified Nafion membranes by modifying the Nafion matrix with organic or inorganic materials with different structures, sizes and compositions, modification techniques, or multilayered systems in order to improve the physical properties of Nafion. The characterization, properties, and performance of DAFCs from various types of modified Nafion membranes are critically reviewed by giving detailed examples. The challenges and future prospects for the modification of Nafion membranes for DAFC applications are also discussed.
154 citations