Membranes

Editorial

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3 pages, 196 KiB

Open AccessEditorial

Ionic Conductive Membranes for Fuel Cells

by Riccardo Narducci

Membranes 2021, 11(3), 159; https://doi.org/10.3390/membranes11030159 - 25 Feb 2021

Viewed by 1422

Abstract

The need to reduce pollution and the continuous increase in petrol cost have reinforced the interest in fuel cells (FCs), efficient and clean systems for the conversion of fuel into energy [...] Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

Research

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18 pages, 2962 KiB

Open AccessArticle

Immobilisation and Release of Radical Scavengers on Nanoclays for Chemical Reinforcement of Proton Exchange Membranes

by Alia Akrout, Aude Delrue, Marta Zatoń, Fanny Duquet, Francesco Spanu, Mélanie Taillades-Jacquin, Sara Cavaliere, Deborah Jones and Jacques Rozière

Membranes 2020, 10(9), 208; https://doi.org/10.3390/membranes10090208 - 28 Aug 2020

Cited by 11 | Viewed by 3080

Abstract

Mechanical and chemical stability of proton exchange membranes are crucial requirements for the development of fuel cells for durable energy conversion. To tackle this challenge, bi-functional nanoclays grafted with amino groups and with embedded radical scavengers, that is, CeO₂ nanoparticles were incorporated [...] Read more.

Mechanical and chemical stability of proton exchange membranes are crucial requirements for the development of fuel cells for durable energy conversion. To tackle this challenge, bi-functional nanoclays grafted with amino groups and with embedded radical scavengers, that is, CeO₂ nanoparticles were incorporated into Aquivion^® ionomer. The composite membranes presented high proton conductivity and increased stability to radical attack compared to non-modified Aquivion membranes, demonstrating the effectiveness of the approach based on radical scavenger immobilisation and release from clay nanocontainers. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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18 pages, 2332 KiB

Open AccessArticle

The Effects of Temperature and Humidity on the Microstructure of Sulfonated Syndiotactic–polystyrene Ionic Membranes

by Maria-Maddalena Schiavone, David Hermann Lamparelli, Yue Zhao, Fengfeng Zhu, Zsolt Revay and Aurel Radulescu

Membranes 2020, 10(8), 187; https://doi.org/10.3390/membranes10080187 - 14 Aug 2020

Cited by 8 | Viewed by 2899

Abstract

Polymeric membranes based on the semi-crystalline syndiotactic–polystyrene (sPS) become hydrophilic, and therefore conductive, following the functionalization of the amorphous phase by the solid-state sulfonation procedure. Because the crystallinity of the material, and thus the mechanical strength of the membranes, is maintained and the [...] Read more.

Polymeric membranes based on the semi-crystalline syndiotactic–polystyrene (sPS) become hydrophilic, and therefore conductive, following the functionalization of the amorphous phase by the solid-state sulfonation procedure. Because the crystallinity of the material, and thus the mechanical strength of the membranes, is maintained and the resistance to oxidation decomposition can be improved by doping the membranes with fullerenes, the sPS becomes attractive for proton-exchange membranes fuel cells (PEMFC) and energy storage applications. In the current work we report the micro-structural characterization by small-angle neutron scattering (SANS) method of sulfonated sPS films and sPS–fullerene composite membranes at different temperatures between 20 °C and 80 °C, under the relative humidity (RH) level from 10% to 70%. Complementary characterization of membranes was carried out by FTIR, UV-Vis spectroscopy and prompt–γ neutron activation analysis in terms of composition, following the specific preparation and functionalization procedure, and by XRD with respect to crystallinity. The hydrated ionic clusters are formed in the hydrated membrane and shrink slightly with the increasing temperature, which leads to a slight desorption of water at high temperatures. However, it seems that the conductive properties of the membranes do not deteriorate with the increasing temperature and that all membranes equilibrated in liquid water show an increased conductivity at 80 °C compared to the room temperature. The presence of fullerenes in the composite membrane induces a tremendous increase in the conductivity at high temperatures compared to fullerenes-free membranes. Apparently, the observed effects may be related to the formation of additional hydrated pathways in the composite membrane in conjunction with changes in the dynamics of water and polymer. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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16 pages, 2614 KiB

Open AccessArticle

Energy Harvesting from Brines by Reverse Electrodialysis Using Nafion Membranes

by Ahmet H. Avci, Diego A. Messana, Sergio Santoro, Ramato Ashu Tufa, Efrem Curcio, Gianluca Di Profio and Enrica Fontananova

Membranes 2020, 10(8), 168; https://doi.org/10.3390/membranes10080168 - 28 Jul 2020

Cited by 29 | Viewed by 5399

Abstract

Ion exchange membranes (IEMs) have consolidated applications in energy conversion and storage systems, like fuel cells and battery separators. Moreover, in the perspective to address the global need for non-carbon-based and renewable energies, salinity-gradient power (SGP) harvesting by reverse electrodialysis (RED) is attracting [...] Read more.

Ion exchange membranes (IEMs) have consolidated applications in energy conversion and storage systems, like fuel cells and battery separators. Moreover, in the perspective to address the global need for non-carbon-based and renewable energies, salinity-gradient power (SGP) harvesting by reverse electrodialysis (RED) is attracting significant interest in recent years. In particular, brine solutions produced in desalination plants can be used as concentrated streams in a SGP-RED stack, providing a smart solution to the problem of brine disposal. Although Nafion is probably the most prominent commercial cation exchange membrane for electrochemical applications, no study has investigated yet its potential in RED. In this work, Nafion 117 and Nafion 115 membranes were tested for NaCl and NaCl + MgCl₂ solutions, in order to measure the gross power density extracted under high salinity gradient and to evaluate the effect of Mg²⁺ (the most abundant divalent cation in natural feeds) on the efficiency in energy conversion. Moreover, performance of commercial CMX (Neosepta) and Fuji-CEM 80050 (Fujifilm) cation exchange membranes, already widely applied for RED applications, were used as a benchmark for Nafion membranes. In addition, complementary characterization (i.e., electrochemical impedance and membrane potential test) was carried out on the membranes with the aim to evaluate the predominance of electrochemical properties in different aqueous solutions. In all tests, Nafion 117 exhibited superior performance when 0.5/4.0 M NaCl fed through 500 µm-thick compartments at a linear velocity 1.5 cm·s⁻¹. However, the gross power density of 1.38 W·m⁻² detected in the case of pure NaCl solutions decreased to 1.08 W·m⁻² in the presence of magnesium chloride. In particular, the presence of magnesium resulted in a drastic effect on the electrochemical properties of Fuji-CEM-80050, while the impact on other membranes investigated was less severe. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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25 pages, 7729 KiB

Open AccessEditor’s ChoiceArticle

Structural, Morphological, Electrical and Electrochemical Properties of PVA: CS-Based Proton-Conducting Polymer Blend Electrolytes

by Ayub Shahab Marf, Ranjdar M. Abdullah and Shujahadeen B. Aziz

Membranes 2020, 10(4), 71; https://doi.org/10.3390/membranes10040071 - 15 Apr 2020

Cited by 65 | Viewed by 3618

Abstract

Polymer blend electrolytes based on poly(vinyl alcohol):chitosan (PVA:CS) incorporated with various quantities of ammonium iodide were prepared and characterized using a range of electrochemical, structural and microscopic techniques. In the structural analysis, X-ray diffraction (XRD) was used to confirm the buildup of the [...] Read more.

Polymer blend electrolytes based on poly(vinyl alcohol):chitosan (PVA:CS) incorporated with various quantities of ammonium iodide were prepared and characterized using a range of electrochemical, structural and microscopic techniques. In the structural analysis, X-ray diffraction (XRD) was used to confirm the buildup of the amorphous phase. To reveal the effect of dopant addition on structural changes, field-emission scanning electron microscope (FESEM) was used. The protrusions of salt aggregates with large quantity were seen at the surface of the formed films at 50 wt.% of the added salt. The nature of the relationship between conductivity and dielectric properties was shown using electrochemical impedance spectroscopy (EIS). The EIS spectra were fitted with electrical equivalent circuits (EECs). It was observed that both dielectric constant and dielectric loss were high in the low-frequency region. For all samples, loss tangent and electric modulus plots were analyzed to become familiar with the relaxation behavior. Linear sweep voltammetry (LSV) and transference number measurement (TNM) were recorded. A relatively high cut-off potential for the polymer electrolyte was obtained at 1.33 V and both values of the transference number for ion (t_ion) and electronic (t_elec) showed the ion dominant as charge carrier species. The TNM and LSV measurements indicate the suitability of the samples for energy storage application if their conductivity can be more enhanced. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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14 pages, 2796 KiB

Open AccessEditor’s ChoiceArticle

Chemically Crosslinked Sulfonated Polyphenylsulfone (CSPPSU) Membranes for PEM Fuel Cells

by Je-Deok Kim, Akihiro Ohira and Hidenobu Nakao

Membranes 2020, 10(2), 31; https://doi.org/10.3390/membranes10020031 - 18 Feb 2020

Cited by 18 | Viewed by 4202

Abstract

Sulfonated polyphenylsulfone (SPPSU) with a high ion exchange capacity (IEC) was synthesized using commercially available polyphenylsulfone (PPSU), and a large-area (16 × 18 cm²) crosslinked sulfonated polyphenylsulfone (CSPPSU) membrane was prepared. In addition, we developed an activation process in which the [...] Read more.

Sulfonated polyphenylsulfone (SPPSU) with a high ion exchange capacity (IEC) was synthesized using commercially available polyphenylsulfone (PPSU), and a large-area (16 × 18 cm²) crosslinked sulfonated polyphenylsulfone (CSPPSU) membrane was prepared. In addition, we developed an activation process in which the membrane was treated with alkaline and acidic solutions to remove sulfur dioxide (SO₂), which forms as a byproduct during heat treatment. CSPPSU membranes obtained using this activation method had high thermal, mechanical and chemical stabilities. In I-V_{iR free} studies for fuel cell evaluation, high performances similar to those using Nafion were obtained. In addition, from the hydrogen (H₂) gas crossover characteristics, the durability is much better than that of a Nafion212 membrane. In the studies evaluating the long-term stabilities by using a constant current method, a stability of 4000 h was obtained for the first time. These results indicate that the CSPPSU membrane obtained by using our activation method is promising as a polymer electrolyte membrane. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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13 pages, 2005 KiB

Open AccessArticle

Study of Annealed Aquivion^® Ionomers with the INCA Method †

by Stefano Giancola, Raul Andres Becerra Arciniegas, Armand Fahs, Jean-Franҫois Chailan, Maria Luisa Di Vona, Philippe Knauth and Riccardo Narducci

Membranes 2019, 9(10), 134; https://doi.org/10.3390/membranes9100134 - 17 Oct 2019

Cited by 14 | Viewed by 4107

Abstract

We investigated the possibility to increase the working temperature and endurance of proton exchange membranes for fuel cells and water electrolyzers by thermal annealing of short side chain perfluorosulfonic acid (SSC-PFSA) Aquivion^® membranes. The Ionomer n_c Analysis (INCA method), based on [...] Read more.

We investigated the possibility to increase the working temperature and endurance of proton exchange membranes for fuel cells and water electrolyzers by thermal annealing of short side chain perfluorosulfonic acid (SSC-PFSA) Aquivion^® membranes. The Ionomer n_c Analysis (INCA method), based on n_c/T plots where n_c is a counter elastic force index, was applied to SSC-PFSA in order to evaluate ionomer thermo-mechanical properties and to probe the increase of crystallinity during the annealing procedure. The enhanced thermal and mechanical stability of extruded Aquivion^® 870 (equivalent weight, EW = 870 g·mol⁻¹) was related to an increase of long-range order. Complementary differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) measurements confirmed the increase of polymer stiffness by the annealing treatment with an enhancement of the storage modulus over the whole range of temperature. The main thermomechanical relaxation temperature is also enhanced. DSC measurements showed slight base line changes after annealing, attributable to the glass transition and melting of a small amount of crystalline phase. The difference between the glass transition and melting temperatures derived from INCA plots and the ionic-cluster transition temperature derived from DMA measurements is consistent with the different experimental conditions, especially the dry atmosphere in DMA. Finally, the annealing procedure was also successfully applied for the first time to an un-crystallized cast membrane (EW = 830 g·mol⁻¹) resulting in a remarkable mechanical and thermal stabilization. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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Review

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53 pages, 3413 KiB

Open AccessReview

Modelling the Proton-Conductive Membrane in Practical Polymer Electrolyte Membrane Fuel Cell (PEMFC) Simulation: A Review

by Edmund J. F. Dickinson and Graham Smith

Membranes 2020, 10(11), 310; https://doi.org/10.3390/membranes10110310 - 28 Oct 2020

Cited by 49 | Viewed by 6236

Abstract

Theoretical models used to describe the proton-conductive membrane in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, within the specific context of practical, physicochemical simulations of PEMFC device-scale performance and macroscopically observable behaviour. Reported models and their parameterisation (especially for Nafion 1100 materials) [...] Read more.

Theoretical models used to describe the proton-conductive membrane in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, within the specific context of practical, physicochemical simulations of PEMFC device-scale performance and macroscopically observable behaviour. Reported models and their parameterisation (especially for Nafion 1100 materials) are compiled into a single source with consistent notation. Detailed attention is given to the Springer–Zawodzinski–Gottesfeld, Weber–Newman, and “binary friction model” methods of coupling proton transport with water uptake and diffusive water transport; alongside, data are compiled for the corresponding parameterisation of proton conductivity, water sorption isotherm, water diffusion coefficient, and electroosmotic drag coefficient. Subsequent sections address the formulation and parameterisation of models incorporating interfacial transport resistances, hydraulic transport of water, swelling and mechanical properties, transient and non-isothermal phenomena, and transport of dilute gases and other contaminants. Lastly, a section is dedicated to the formulation of models predicting the rate of membrane degradation and its influence on PEMFC behaviour. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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18 pages, 1411 KiB

Open AccessReview

Insights into Advancements and Electrons Transfer Mechanisms of Electrogens in Benthic Microbial Fuel Cells

by Mohammad Faisal Umar, Syed Zaghum Abbas, Mohamad Nasir Mohamad Ibrahim, Norli Ismail and Mohd Rafatullah

Membranes 2020, 10(9), 205; https://doi.org/10.3390/membranes10090205 - 28 Aug 2020

Cited by 41 | Viewed by 4861

Abstract

Benthic microbial fuel cells (BMFCs) are a kind of microbial fuel cell (MFC), distinguished by the absence of a membrane. BMFCs are an ecofriendly technology with a prominent role in renewable energy harvesting and the bioremediation of organic pollutants through electrogens. Electrogens act [...] Read more.

Benthic microbial fuel cells (BMFCs) are a kind of microbial fuel cell (MFC), distinguished by the absence of a membrane. BMFCs are an ecofriendly technology with a prominent role in renewable energy harvesting and the bioremediation of organic pollutants through electrogens. Electrogens act as catalysts to increase the rate of reaction in the anodic chamber, acting in electrons transfer to the cathode. This electron transfer towards the anode can either be direct or indirect using exoelectrogens by oxidizing organic matter. The performance of a BMFC also varies with the types of substrates used, which may be sugar molasses, sucrose, rice paddy, etc. This review presents insights into the use of BMFCs for the bioremediation of pollutants and for renewable energy production via different electron pathways. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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18 pages, 2840 KiB

Open AccessEditor’s ChoiceReview

New Perspectives on Fuel Cell Technology: A Brief Review

by Norazlianie Sazali, Wan Norharyati Wan Salleh, Ahmad Shahir Jamaludin and Mohd Nizar Mhd Razali

Membranes 2020, 10(5), 99; https://doi.org/10.3390/membranes10050099 - 13 May 2020

Cited by 183 | Viewed by 18715

Abstract

Energy storage and conversion is a very important link between the steps of energy production and energy consumption. Traditional fossil fuels are a natural and unsustainable energy storage medium with limited reserves and notorious pollution problems, therefore demanding a better choice to store [...] Read more.

Energy storage and conversion is a very important link between the steps of energy production and energy consumption. Traditional fossil fuels are a natural and unsustainable energy storage medium with limited reserves and notorious pollution problems, therefore demanding a better choice to store and utilize the green and renewable energies in the future. Energy and environmental problems require a clean and efficient way of using the fuels. Fuel cell functions to efficiently convert oxidant and chemical energy accumulated in the fuel directly into DC electric, with the by-products of heat and water. Fuel cells, which are known as effective electrochemical converters, and electricity generation technology has gained attention due to the need for clean energy, the limitation of fossil fuel resources and the capability of a fuel cell to generate electricity without involving any moving mechanical part. The fuel cell technologies that received high interest for commercialization are polymer electrolyte membrane fuel cells (PEMFCs), solid oxide fuel cells (SOFCs), and direct methanol fuel cells (DMFCs). The optimum efficiency for the fuel cell is not bound by the principle of Carnot cycle compared to other traditional power machines that are generally based on thermal cycles such as gas turbines, steam turbines and internal combustion engines. However, the fuel cell applications have been restrained by the high cost needed to commercialize them. Researchers currently focus on the discovery of different materials and manufacturing methods to enhance fuel cell performance and simplify components of fuel cells. Fuel cell systems’ designs are utilized to reduce the costs of the membrane and improve cell efficiency, durability and reliability, allowing them to compete with the traditional combustion engine. In this review, we primarily analyze recent developments in fuel cells technologies and up-to-date modeling for PEMFCs, SOFCs and DMFCs. Full article

(This article belongs to the Special Issue Ionic Conductive Membranes for Fuel Cells)

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