Solubility and transport behavior of water and alcohols in Nafion™

Rivin, D.; Kendrick, Chito; Gibson, Phillip; Schneider, N. S.

doi:10.1016/s0032-3861(00)00350-5

Cited by 224 publications

(224 citation statements)

References 27 publications

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“…The reference potential is determined by thermodynamics as described above (e.g., equation 6), where the same (imaginary) reference electrode should be used for calculation of the electronic and ionic potentials. The term in parentheses in equation 27 can be written in terms of an electrode overpotential [56] If the reference electrode is exposed to the conditions at the reaction site, then a surface or kinetic overpotential can be defined…”

Section: Basic Governing Equationsmentioning

confidence: 99%

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Weber

Borup

Darling³

et al. 2014

J. Electrochem. Soc.

509

394

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Polymer-electrolyte fuel cells are a promising energy-conversion technology. Over the last several decades significant progress has been made in increasing their performance and durability, of which continuum-level modeling of the transport processes has played an integral part. In this review, we examine the state-of-the-art modeling approaches, with a goal of elucidating the knowledge gaps and needs going forward in the field. In particular, the focus is on multiphase flow, especially in terms of understanding interactions at interfaces, and catalyst layers with a focus on the impacts of ionomer thin-films and multiscale phenomena. Overall, we highlight where there is consensus in terms of modeling approaches as well as opportunities for further improvement and clarification, including identification of several critical areas for future research. Fuel cells may become the energy-delivery devices of the 21 st century. Although there are many types of fuel cells, polymer-electrolyte fuel cells (PEFCs) are receiving the most attention for automotive and small stationary applications. In a PEFC, fuel and oxygen are combined electrochemically. If hydrogen is used as the fuel, it oxidizes at the anode releasing proton and electrons according toThe generated protons are transported across the membrane and the electrons across the external circuit. At the cathode catalyst layer, protons and electrons recombine with oxygen to generate waterAlthough the above electrode reactions are written in single step, multiple elementary reaction pathways are possible at each electrode. During the operation of a PEFC, many interrelated and complex phenomena occur. These processes include mass and heat transfer, electrochemical reactions, and ionic and electronic transport. * Electrochemical Society Active Member. z E-mail: azweber@lbl.govOver the last several decades significant progress has been made in increasing PEFC performance and durability. Such progress has been enabled by experiments and computation at multiple scales, with the bulk of the focus being on optimizing and discovering new materials for the membrane-electrode-assembly (MEA), composed of the proton-exchange membrane (PEM), catalyst layers, and diffusionmedia (DM) backing layers. In particular, continuum modeling has been invaluable in providing understanding and insight into processes and phenomena that cannot be resolved or uncoupled through experiments. While modeling of the transport and related phenomena has progressed greatly, there are still some critical areas that need attention. These areas include modeling the catalyst layer and multiphase phenomena in the PEFC porous media.While there have been various reviews over the years of PEFC modeling 1-7 and issues, [8][9][10][11][12][13][14] as well as numerous books and book chapters, there is a need to examine critically the field in terms of what has been done and what needs to be done. This review serves that purpose with a focus on transport modeling of PEFCs. This is not meant to be an exhaustive review...

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Section: Basic Governing Equationsmentioning

confidence: 99%

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Weber

Borup

Darling³

et al. 2014

J. Electrochem. Soc.

509

394

View full text Add to dashboard Cite

show abstract

“…Probably due to possible differences in the membrane pretreatment, the liquid uptake values obtained in this study are lower than those reported by others. As an example, the solubilities in NF117 reported by Rivin et al 26 are as follows: water, 0.22 g/g; methanol, 0.492 g/g; propanol, 0.486 g/g. In NF117, the polytetrafluoroethylene backbone is highly hydrophobic, whereas the sulfonic groups are very hydrophilic.…”

Section: Resultsmentioning

confidence: 94%

Fluid flow modeling in a sulfonated cation‐exchange membrane

Villaluenga

Barragán

Izquierdo-Gil

et al. 2009

J of Applied Polymer Sci

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Liquid permeation measurements of water, methanol, and 2-propanol were carried out using a commercial cation-exchange membrane Nafion-117 (perfluorinated polyethylene with pendant ether-linked side chains terminated with sulfonated groups). The experimental permeation data are treated and analyzed using the capillary model, leading to the determination of equivalent pore radius of the membrane structure.

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“…Figure 1a shows the increase in the steady-state concentrations of formic acid, methanol, ethanol, and propanol as functions of the cell current densities. These concentrations were determined assuming equal areas of catalyst (same as the area of the cathode) and ion-exchange membrane, and are based on the permeability of formic acid, 23 and alcohols 11 through Nafion 117. The steady-state concentration of formic acid is higher than that of alcohols because of its higher stoichiometric number (0.5) per electron transferred.…”

Section: Phase Equilibrium Of Salt-ethanol-water Mixturesmentioning

confidence: 99%

Design of an artificial photosynthetic system for production of alcohols in high concentration from CO₂

Singh

Bell

2016

Energy Environ. Sci.

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Artificial photosynthesis of liquid fuels is a potential source for clean energy. Of particular interest is the formation of alcohols because Alcohols are particularly attractive products because of their high energy density and market value per amount of energy input. The major challenges in photo/electrochemical synthesis of alcohols from sunlight, water and CO2 are low product selectivity, high membrane fuel crossover losses, and high cost of product separation from the electrolyte. Here we propose an artificial photosynthesis scheme for direct synthesis and separation to almost pure ethanol with minimum product crossover using saturated salt electrolytes. The ethanol produced in the saturated salt electrolytes can be readily phase separated into a microemulsion, which can be collected as pure products in a liquid-liquid extractor. A novel design of an integrated artificial photosynthetic system is proposed that continuously produces >90 wt% pure ethanol using a polycrystalline copper anode and an IrO2 cathode at a current density of 0.85 mA cm -2 . The annual production rate of > 90 wt% ethanol using such a photosynthesis system operating at 10 mA cm -2 (12% solar-to-fuel (STF) efficiency) can be 15.27 million gallons per year per square kilometer, which corresponds to 7% of the industrial ethanol production capacity of California.

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Solubility and transport behavior of water and alcohols in Nafion™

Cited by 224 publications

References 27 publications

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Fluid flow modeling in a sulfonated cation‐exchange membrane

Design of an artificial photosynthetic system for production of alcohols in high concentration from CO₂

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Solubility and transport behavior of water and alcohols in Nafion™

Cited by 224 publications

References 27 publications

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Fluid flow modeling in a sulfonated cation‐exchange membrane

Design of an artificial photosynthetic system for production of alcohols in high concentration from CO2

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Design of an artificial photosynthetic system for production of alcohols in high concentration from CO₂