Nafion

About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.

Water transport behavior in Nafion 117 membranes

Abstract: The water transport behavior in Nafion 117 cation exchange membrane was studied using the streaming potential method. The water transference coefficient of the membranes in the H{sup +} form was found to be 2.6. The results also show that Nafion 117 membranes have a good cation selectivity performance in HCl solutions within a concentration range between 0.003 and 1N. The water transference coefficients of the membranes equilibrated with alkali metal chlorides and alkaline earth metal chlorides solutions were investigated as well. It was found that the water transport behavior is related to the surface-charge density, hydration enthalpy of the cations exchanged in the membranes, and water content of the membrane. The effect diameter of the micropore in Nafion 117 was estimated as 0.8 to 1.3 nm.

Hybrid Anion and Proton Exchange Membrane Fuel Cells

Abstract: A novel hybrid fuel cell is described using at least one electrode operating at high pH in an effort to use the high conductivity of Nafion and exploit the electrochemical advantages of high-pH operation. The electrochemical behavior of a hybrid anion exchange membrane (AEM)/proton exchange membrane (PEM) junction and corresponding fuel cell are presented. Two AEM/PEM junctions and fuel cells have been evaluated: AEM anode/PEM cathode and PEM anode/AEM cathode. The AEM cathode/PEM membrane configuration causes proton−hydroxide recombination at the membrane junction, resulting in self-hydration of the membrane. The fuel cell performance improves at lower relative humidity. At 65 °C and 0% relative humidity, the hybrid cell operates at steady state whereas the performance of a conventional PEM cell decreases with time due to dry-out.

Fast Ion Conduction in Layer-By-Layer Polymer Films

Abstract: The layer-by-layer (LBL) deposition technique has been applied to the design of polymer electrolyte films appropriate for electrochemical applications such as sensors and electrochromic cells. In this work, we describe the properties of three LBL polymer electrolyte systems assembled from cationic layers of linear poly(ethylene imine) (LPEI), with anionic layers of Nafion, poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), and poly(acrylic acid) (PAA). The assembly behavior of these systems was carefully examined, and ionic conductivity was determined using impedance spectroscopy. The influences of assembly conditions and water plasticization on ion conduction were elaborated. Room-temperature ionic conductivity greater than 10-5 S/cm can be achieved within LPEI/PAMPS and LPEI/PAA films, which is 2 orders of magnitude greater than the highest values previously described in LBL films. By manipulating a unique assembly mechanism, high ionic conductivity can be achieved in LPEI/PAMPS films at low pl...