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1
Su, Dong Yun, Jun Ma, and Hai Kun Pu. "The Research of Nafion/PTFE/Inorganic Composite Membrane Used in Direct Methanol Fuel Cell." Advanced Materials Research 881-883 (January 2014): 927–30. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.927.
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PTFE/Nafion (PN) membranes were fabricated for the application of moderate and high temperature proton exchange membrane fuel cells (PEMFCs), respectively. Membrane electrode assemblies (MEAs) were fabricated by PTFE/Nafion membranes with commercially available low and high temperature gas diffusion electrodes (GDEs).The influence of [ZrOCl2]/[Nafio wt. ratio of Nafion/ZrOCl2 solution on the membrane morphology of NFZrP and PEMFCs performance was investigated. And the influence of hybridizing silicate into the PN membranes on their direct methanol fuel cell (DMFC) performance and methanol crossover was investigated. Silicate in PN membranes causes reduction both in proton conductivity and methanol crossover of membranes. Due to the low conductivity of PTFE and silicate, PNS had a higher proton resistance than Nafion-112.The effects of introducing sub-μm porous PTFE film and ZrP particles into Nafion membranes on the DMFC performance were investigated. The influence of ZrP hybridizing process into NF membranes on the morphology of NFZrP composite membranes and thus on the DMFC performance was also discussed.
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Kim, Young Ho, Hyun Kyu Lee, Youn Jin Park, Yoon Ji Lee, A. I. Gopalan, Kwang Pill Lee, and Sang June Choi. "Preparation of a Styrenesulfonate Grafted MWCNT/Nafion® Nanocomposite Membrane for Direct Methanol Fuel Cell Applications." Advanced Materials Research 347-353 (October 2011): 3685–90. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3685.
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Styrenesulfonate grafted multi-walled carbon nanotubes (ss-MWCNTs) were prepared by a simple chemical reaction with soduim 4-styrenesulfonate to reinforce Nafion® membranes for use in direct methanol fuel cells (DMFCs). Although Nafion® membranes have excellent proton conductivity for fuel cell applications, methanol crossover through the Nafion® membrane remains a serious problem for DMFC applications. The prepared ss-MWCNTs had approximately 3.30 wt.% of sulfure and showed styrenesulfonate groups on the ss-MWCNTs. Then, the Nafion® membranes were reinforced with ss-MWCNTs to reduce methanol crossover. The styrenesulfonate groups on the ss-MWCNTs contained sulfonate end groups that enhanced miscibility of MWCNTs in the Nafion® membrance because of affinity of the same sulfonate groups in the ss-MWCNTs and the Nafion® membrane. Further, the phenyl structure of the styrenesulfonate groups on the ss-MWCNTs enhanced thermal stability at high temperature. The Nafion® membranes were reinforced with ss-MWCNTs (1 wt.%) using a solution casting with a certain amount of water and sodium 4-styrenesulfonate. Well-dispersed 1 wt.% ss-MWCNT reinforced Nafion® membranes were prepared, and the water and methanol uptake were investigated for DMFC applications. The methanol uptake value (36.84) of the 1 wt.% ss-MWCNT reinforced Nafion® membranes was reduced compared to that of the cast Nafion® membrane (38.85).
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Nah, C., S. K. Kwak, N. Kim, M. Y. Lyu, B. S. Hwang, B. Akle, and D. J. Leo. "Ionic Liquid Nafion Nanofiber Mats Composites for High Speed Ionic Polymer Actuators." Key Engineering Materials 334-335 (March 2007): 1001–4. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.1001.
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A new attempt is made for application of the NafionTM nanofiber mat prepared by the electrospinning process to solve the main disadvantage of slow response speed of ionomer-ionic liquid transducers. The measured conductivities of water hydrated Nafion electro-spun fibers are 16.8 mS/cm, which are lower than the nominal 110 mS/cm that of H+ Nafion membranes. The uptake is measured to be around 250 wt % compared to 58 wt % obtained in Nafion films. The ionic conductivity of 110 wt % swollen ionic liquids-Nafion mat composite is computed to be 0.9 mS/cm compared to 0.3 mS/cm in ionic liquid-Nafion membrane composite. The speed of response in actuators with an ionic liquid- NafionTM mat is 1.34 %/s compared to 0.88 %/s for that in ionic liquid NafionTM film transducers.
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Haryadi, Y. B. Gunawan, S. P. Mursid, and D. Haryogi. "Characterization of Nafion/Silica Hybrid Composite Membranes for Redox Flow Battery (RFB) Applications." Advanced Materials Research 911 (March 2014): 45–49. http://dx.doi.org/10.4028/www.scientific.net/amr.911.45.
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Nafion/Silica hybrid membranes were preparedvia in situsolgel method for redox flow battery (RFB) system. In this work, a novel Nafion/organically modified silicate hybrids nanocomposite membrane was preparedvia in situsolgel reactions for mixtures of tetraethoxysilane (TEOS) and trimethoxyprohanthiol (TMSP). The primary properties of Nafion/Silica hybrids membrane were measured and compared with Nafion and Nafion/SiO2hybrid membranes. Fourier transform infrared spectra (FT-IR) analysis of the hybrids membranes reveal that the silica and organic modified silica phase is well formed within hybrids membrane. The XRD results indicate thatthe Nafionhybrid membranes are not influenced by SiO2nanoparticles.Nafion/Silica hybrid membrane shows nearly the same ion exchange capacity (IEC) and slightly greater of proton conductivity as pristine Nafion-117 membrane. The water uptake for Nafion/Organosilica hybrids membrane shows greatly reduced than a pristine Nafion 117, suggesting of low water cross over that is mostly faced in the RFB applications.
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Safronova, Ekaterina Yu, Daria Yu Voropaeva, Anna A. Lysova, Oleg V. Korchagin, Vera A. Bogdanovskaya, and Andrey B. Yaroslavtsev. "On the Properties of Nafion Membranes Recast from Dispersion in N-Methyl-2-Pyrrolidone." Polymers 14, no. 23 (December 2, 2022): 5275. http://dx.doi.org/10.3390/polym14235275.
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Perfluorosulfonic acid Nafion membranes are widely used as an electrolyte in electrolysis processes and in fuel cells. Changing the preparation and pretreatment conditions of Nafion membranes allows for the optimization of their properties. In this work, a Nafion-NMP membrane with a higher conductivity than the commercial Nafion® 212 membrane (11.5 and 8.7 mS∙cm−1 in contact with water at t = 30 °C) and a comparable hydrogen permeability was obtained by casting from a Nafion dispersion in N-methyl-2-pyrrolidone. Since the ion-exchange capacity and the water uptake of these membranes are similar, it can be assumed that the increase in conductivity is the result of optimizing the Nafion-NMP microstructure by improving the connectivity of the pores and channels system. This leads to a 27% increase in the capacity of the membrane electrode assembly with the Nafion-NMP membrane compared to the Nafion® 212 membrane. Thus, the method of obtaining a Nafion membrane has a great influence on its properties and performance of fuel cells based on them.
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Romero, V., M. V. Martínez de Yuso, A. Arango, E. Rodríguez-Castellón, and J. Benavente. "Modification of Nafion Membranes by IL-Cation Exchange: Chemical Surface, Electrical and Interfacial Study." International Journal of Electrochemistry 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/349435.
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Bulk and surface changes in two proton-exchange membranes (Nafion-112 and Nafion-117) as a result of the incorporation of the IL-cationn-dodecyltriethylammonium (or DTA+) by a proton/cation exchange mechanism after immersion in a DTA+aqueous solution were analysed by impedance spectroscopy (IS), differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and contact angle measurements performed with dry samples of the original Nafion and Nafion-DTA+-modified membranes. Only slight differences were obtained in the incorporation degree and surface chemical nature depending on the membrane thickness, and DTA+incorporation modified both the hydrophobic character of the original Nafion membranes and their thermal stability. Electrical characterization of the dry Nafion-112 membrane was performed by impedance spectroscopy while different HCl solutions were used for membrane potential measurements. A study of time evolution of the impedance curves measured in the system “IL aqueous solution/Nafion-112 membrane/IL aqueous solution” was also performed. This study allows us monitoring the electrical changes associated to the IL-cation incorporation in both the membrane and the membrane/IL solution interface, and it provides supplementary information on the characteristic of the Nafion/DTA+hybrid material. Moreover, the results also show the significant effect of water on the electrical resistance of the Nafion-112/IL-cation-modified membrane.
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Lufrano, Ernestino, Cataldo Simari, Maria Luisa Di Vona, Isabella Nicotera, and Riccardo Narducci. "How the Morphology of Nafion-Based Membranes Affects Proton Transport." Polymers 13, no. 3 (January 22, 2021): 359. http://dx.doi.org/10.3390/polym13030359.
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This work represents a systematic and in-depth study of how Nafion 1100 membrane preparation procedures affect both the morphology of the polymeric film and the proton transport properties of the electrolyte. The membrane preparation procedure has non-negligible consequences on the performance of the proton-exchange membrane fuel cells (PEMFC) that operate within a wide temperature range (up to 120 °C). A comparison between commercial membranes (Nafion 117 and Nafion 212) and Nafion membranes prepared by three different procedures, namely (a) Nafion-recast, (b) Nafion uncrystallized, and (c) Nafion 117-oriented, was conducted. Electrochemical Impedance Spectroscopy (EIS) and Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) investigations indicated that an anisotropic morphology could be achieved when a Nafion 117 membrane was forced to expand between two fixed and nondeformable surfaces. This anisotropy increased from ~20% in the commercial membrane up to 106% in the pressed membrane, where the ionic clusters were averagely oriented (Nafion 117-oriented) parallel to the surface, leading to a strong directionality in proton transport. Among the membranes obtained by solution-cast, which generally exhibited isotropic proton transport behavior, the Nafion uncrystallized membrane showed the lowest water diffusion coefficients and conductivities, highlighting the correlation between low crystallinity and a more branched and tortuous structure of hydrophilic channels. Finally, the dynamic mechanical analysis (DMA) tests demonstrated the poor elastic modulus for both uncrystallized and oriented membranes, which should be avoided in high-temperature fuel cells.
8
Selim, Asmaa, Gábor Pál Szijjártó, and András Tompos. "Insights into the Influence of Different Pre-Treatments on Physicochemical Properties of Nafion XL Membrane and Fuel Cell Performance." Polymers 14, no. 16 (August 18, 2022): 3385. http://dx.doi.org/10.3390/polym14163385.
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Perfluorosulfonic acid (PFSA) polymers such as Nafion are the most frequently used Proton Exchange Membrane (PEM) in PEM fuel cells. Nafion XL is one of the most recently developed membranes designed to enhance performance by employing a mechanically reinforced layer in the architecture and a chemical stabilizer. The influence of the water and acid pre-treatment process on the physicochemical properties of Nafion XL membrane and Membrane Electrode Assembly (MEA) was investigated. The obtained results indicate that the pre-treated membranes have higher water uptake and dimensional swelling ratios, i.e., higher hydrophilicity, while the untreated membrane demonstrated a higher ionic exchange capacity. Furthermore, the conductivity of the acid pre-treated Nafion XL membrane was ~ 9.7% higher compared to the untreated membrane. Additionally, the maximum power densities obtained at 80 °C using acid pre-treatment were ~ 0.8 and 0.93 W/cm2 for re-cast Nafion and Nafion XL, respectively. However, the maximum generated powers for untreated membranes at the same condition were 0.36 and 0.66 W/cm2 for re-cast Nafion and Nafion XL, respectively. The overall results indicated that the PEM’s pre-treatment process is essential to enhance performance.
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Mokhtaruddin, Siti Rahmah, Abu Bakar Mohamad, Loh Kee Shyuan, Abdul Amir Hassan Kadhum, and Mahreni Akhmad. "Preparation and Characterization of Nafion-Zirconia Composite Membrane for PEMFC." Advanced Materials Research 239-242 (May 2011): 263–68. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.263.
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Polymer electrolyte membrane based on Nafion and zirconium oxide (ZrO2) was developed via film casting method. The content of ZrO2 (1.0, 2.0, and 3.0 wt.%) was incorporated with Nafion solution to prepare Nafion-ZrO2 composite membranes. Recast Nafion membrane was used as reference material. All of the prepared membranes have been subjected to both physical and chemical characterizations such as Fourier transform infra-red (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) analysis, water uptake rate (WUR) and conductivity measurements. The Nafion-ZrO2 composite membranes were found to possess high thermal stability (Tg= 188 - 192°C) and conductivity (0.30 – 0.93 S cm-1). This study demonstrates the possibility of developing Nafion-ZrO2 composite membrane as promising polymer electrolyte membrane for fuel cell operated at medium temperature and low humidity.
10
Jung, Guo-Bin, Ay Su, Cheng-Hsin Tu, Fang-Bor Weng, Shih-Hung Chan, Ruey-Yi Lee, and Szu-Han Wu. "Supported Nafion Membrane for Direct Methanol Fuel Cell." Journal of Fuel Cell Science and Technology 4, no. 3 (October 4, 2006): 248–54. http://dx.doi.org/10.1115/1.2743069.
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The performances of direct methanol fuel cells are largely dependent on the methanol crossover, while the amount of methanol crossover is reported to strongly rely on membrane materials and thickness. In this research, two new membranes (Nafion 211 and Nx-424), along with well-known Nafion 117 and 112 were studied as electrolytes in the direct methanol fuel cells (DMFC). The Nafion 211 is the thinnest and latest membrane of Nafion series products and Nx-424 is a Nafion membrane with polytetrafluoroethylene (PTFE) fibers as mechanical reinforcement. Nx-424 is used primarily for chloro-alkali production and the electrolytic processes. Although open circuit voltage provides a quick way to evaluate the effect of methanol crossover, the amount of methanol crossover through the membranes was studied in detail via the electrochemical oxidation technique. Both methods show the same trend of methanol crossover of different membranes in this study. Nafion 211 was found to present the highest degree of methanol crossover, however, its’ best performance implied the fact that the influence of the cell resistance (membrane thickness) is dominated in the traditional Nafion system. Although Nafion membrane with thicker thickness and PTFE fiber within Nx-424 provided higher resistance for methanol to cross through, the negative effects of its’ hydrophobic properties also prevent the transport of H2O accompanied by the proton. Therefore, the cell performance of Nx-424 is lower both due to poor proton conductivity and thickest membrane. In other words, the cell performances of traditional Nafion series membranes (Nafion 211, 112, 117) were fully controlled by the thickness while Nx-424 was controlled both by its’ blend properties (hydrophilic-Nafion and hydrophobic-PTFE ) and thickness.
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Goh, Jonathan Teik Ean, Ainul Rasyidah Abdul Rahim, Mohd Shahbudin Masdar, and Loh Kee Shyuan. "Enhanced Performance of Polymer Electrolyte Membranes via Modification with Ionic Liquids for Fuel Cell Applications." Membranes 11, no. 6 (May 27, 2021): 395. http://dx.doi.org/10.3390/membranes11060395.
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The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.
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Kerres, Jochen Alfred, Muhammad Mu’min Solihul, Miriam Komma, Thomas Böhm, Maximilian Wagner, Anja Krieger, and Simon Thiele. "Nafion Composite Membrane Reinforced By Phosphonated Polypentafluorostyrene Nanofibers." ECS Meeting Abstracts MA2022-02, no. 41 (October 9, 2022): 1500. http://dx.doi.org/10.1149/ma2022-02411500mtgabs.
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The membrane is one of the crucial components of fuel cells. Applying composite membranes for fuel cells is a promising option due to better mechanical properties compared to membranes without reinforcement. Composite membranes can be prepared by combining ionomer with a filler which can be selected from many types of materials, such as polymers, ceramics, carbons, and metals. Filler materials exist in different nanostructures which provide flexible designs for composite membranes. However, the main issue in composite membranes is a trade-off among properties when adjusting the ratio between ionomer and filler, especially between ionic conductivity and mechanical modulus. On the one hand, maintaining high protonic conductivity is possible when small concentrations of reinforcing fillers are incorporated. On the other hand, a high amount of reinforcement can improve the mechanical properties significantly but could result in low protonic conductivity as well. Our strategy to overcome this issue is by employing protonic conductive nanofibers as reinforcement. Electrospinning is a versatile method to transform polymer solutions into long and solid nanofibers. Electrospun fibermats possess a high porosity and contain voids which can be filled with an ionomer like Nafion by spraycoating to form a dense composite membrane. We were successful in producing electrospun nanofibers from phosphonated polypentafluorostyrene (PWN70) and unmodified polypentafluorostyrene (PPFSt). PWN70/Nafion and PPFSt/Nafion composite membranes were prepared separately by spraycoating of a Nafion solution into PWN70 and PPFSt fibermats that have comparable thickness and fiber loading. From tensile tests, we found that composite membranes made from PWN70/Nafion and PPFSt/Nafion have much higher Youngs’ modulus (E) than pure Nafion (Figure 1A). Although PWN70/Nafion is a relatively brittle membrane, it has the best Youngs’ modulus and yield stress. Protonic conductivity is also a crucial membrane property which can be determined by electrochemical impedance spectroscopy. In Figure 1B, Nafion reinforced by PPFSt fibers has a reduced conductivity due to non-ion-conductive PPFSt. Surprisingly, the protonic conductivity of a PWN70/Nafion composite membrane is similar to spraycoated Nafion. Without reducing much the protonic conductivity, the PWN70/Nafion composite membrane shows comparable ohmic resistance to the spraycoated D2020 in fuel cell operation which has also been done in this work. Since the PWN70 nanofibers are ion-conductive and electro-spinnable, the nanofibers offer benefits when designing fiber-reinforced composite membrane possessing both good mechanical stability and protonic conductivity. Figure 1
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Sigwadi, Rudzani, Fulufhelo Ṋemavhola, Simon Dhlamini, and Touhani Mokrani. "Mechanical Strength Of Nafion®/ZrO2 Nano-Composite Membrane." International Journal of Manufacturing, Materials, and Mechanical Engineering 8, no. 1 (January 2018): 54–65. http://dx.doi.org/10.4018/ijmmme.2018010104.
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The mechanical stability of modified membranes has become a priority for fuel cell applications as the membranes must endure all the fuel cell operations (to prevent crossover of the fuel while still conducting). Their mechanical stress and yielding stress in the recast and impregnation methods compared with the commercial Nafion® membrane were observed under tensile tests. The modulus of elasticity of wet commercial Nafion117 membrane, Nafion®/ Zr-0, Nafion®/Zr-50 and Nafion®/ Zr-80 membranes and Nafion®/ Zr-100 nano-composite membrane using impregnation methods in the region between 0 and 0.23 strain were determined to be 4817.5 kPa, 2434.7 kPa, 1872.4 kPa, 2092.1 kPa and 2661.4 kPa respectively. The tensile strength of the dry nano-composite membrane prepared using the recast method is higher than the wet nano-composite membrane prepared using the recast methods. It was found that the impregnation method plays an important role in strengthening the nan-composite membranes.
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Kim, Young Ho, Yeon Kyung Lee, Bong Keun Kang, Hee Jin Kim, and Sang June Choi. "Morphological and Thermal Characterization of Nafion/CNT/PVA Nanocomposite Membranes." Key Engineering Materials 729 (February 2017): 68–74. http://dx.doi.org/10.4028/www.scientific.net/kem.729.68.
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Nafion membranes were reinforced by adding functionalized carbon nanotubes (CNTs) such as oxidized CNTs (ox-CNTs). To enhance the ox-CNTs’ miscibility in the Nafion membrane, a small amount of polyvinyl alcohol (PVA) was introduced during the fabrication of some of the nanocomposite membranes. Nafion, a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer, can be used as an ion-exchange membrane in various nanobio-devices. However, some physical properties of Nafion membranes, including the thermal stability, need to be enhanced by adding rigid inorganic nanomaterials such as CNTs or silicates.In this study, PVA-reinforced Nafion membranes with either pristine CNTs (p-CNTs) or ox-CNTs (Nafion/CNT/PVA) were prepared by solution casting. The prepared Nafion/CNT/PVA nanocomposite membranes were approximately 90 μm thick, and their morphologies were characterized by microscopy. Their thermal properties were investigated by differential scanning calorimetry and thermogravimetric analysis.
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Kim, Je Deok, and Mun Suk Jun. "Nafion – Azole Composite Membranes for High Temperature PEMFC." Materials Science Forum 783-786 (May 2014): 1692–97. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1692.
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Nafion-azole (benzimidazole, 1,2,4-triazole, 1,2,3-triazole) composite membranes were prepared by room temperature and autoclave solution processing for high temperature (above 100 °C) PEMFC. Among the various Nafion – azole composite membranes, Nafion – 1,2,3-triazole membrane showed excellent flexibility, thermal stability, and homogeneous structure. Nafion – 1,2,4-triazole composite membrane had high thermal and mechanical properties, and also showed high proton conductivity of 0.02 S/cm at the temperature of 160 °C under dry (N2) condition.
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Sen, Unal, Mehmet Ozdemir, Mustafa Erkartal, Alaattin Metin Kaya, Abdullah A. Manda, Ali Reza Oveisi, M. Ali Aboudzadeh, and Takashi Tokumasu. "Mesoscale Morphologies of Nafion-Based Blend Membranes by Dissipative Particle Dynamics." Processes 9, no. 6 (June 2, 2021): 984. http://dx.doi.org/10.3390/pr9060984.
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Polymer electrolyte membrane (PEM) composed of polymer or polymer blend is a vital element in PEM fuel cell that allows proton transport and serves as a barrier between fuel and oxygen. Understanding the microscopic phase behavior in polymer blends is very crucial to design alternative cost-effective proton-conducting materials. In this study, the mesoscale morphologies of Nafion/poly(1-vinyl-1,2,4-triazole) (Nafion-PVTri) and Nafion/poly(vinyl phosphonic acid) (Nafion-PVPA) blend membranes were studied by dissipative particle dynamics (DPD) simulation technique. Simulation results indicate that both blend membranes can form a phase-separated microstructure due to the different hydrophobic and hydrophilic character of different polymer chains and different segments in the same polymer chain. There is a strong, attractive interaction between the phosphonic acid and sulfonic acid groups and a very strong repulsive interaction between the fluorinated and phosphonic acid groups in the Nafion-PVPA blend membrane. By increasing the PVPA content in the blend membrane, the PVPA clusters’ size gradually increases and forms a continuous phase. On the other hand, repulsive interaction between fluorinated and triazole units in the Nafion-PVTri blend is not very strong compared to the Nafion-PVPA blend, which results in different phase behavior in Nafion-PVTri blend membrane. This relatively lower repulsive interaction causes Nafion-PVTri blend membrane to have non-continuous phases regardless of the composition.
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Li, Jinchao, Jun Liu, Wenjie Xu, Jun Long, Wenheng Huang, Zhen He, Suqin Liu, and Yaping Zhang. "A Sulfonated Polyimide/Nafion Blend Membrane with High Proton Selectivity and Remarkable Stability for Vanadium Redox Flow Battery." Membranes 11, no. 12 (November 29, 2021): 946. http://dx.doi.org/10.3390/membranes11120946.
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A sulfonated polyimide (SPI)/Nafion blend membrane composed of a designed and synthesized SPI polymer and the commercial Nafion polymer is prepared by a facile solution casting method for vanadium redox flow battery (VRFB). Similar molecular structures of both SPI and Nafion provide good compatibility and complementarity of the blend membrane. ATR-FTIR, 1H-NMR, AFM, and SEM are used to gain insights on the chemical structure and morphology of the blend membrane. Fortunately, the chemical stability of the SPI/Nafion blend membrane is effectively improved compared with reported SPI-based membranes for VRFB applications. In cycling charge-discharge tests, the VRFB with the as-prepared SPI/Nafion blend membrane shows excellent battery efficiencies and operational stability. Above results indicate that the SPI/Nafion blend membrane is a promising candidate for VRFB application. This work opens up a new possibility for fabricating high-performance SPI-based blend membrane by introduction of a polymer with a similar molecular structure and special functional groups into the SPI polymer.
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Sigwadi, Rudzani, Touhami Mokrani, Phumlani Msomi, and Fulufhelo Nemavhola. "The Effect of Sulfated Zirconia and Zirconium Phosphate Nanocomposite Membranes on Fuel-Cell Efficiency." Polymers 14, no. 2 (January 10, 2022): 263. http://dx.doi.org/10.3390/polym14020263.
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To investigate the effect of acidic nanoparticles on proton conductivity, permeability, and fuel-cell performance, a commercial Nafion® 117 membrane was impregnated with zirconium phosphates (ZrP) and sulfated zirconium (S-ZrO2) nanoparticles. As they are more stable than other solid superacids, sulfated metal oxides have been the subject of intensive research. Meanwhile, hydrophilic, proton-conducting inorganic acids such as zirconium phosphate (ZrP) have been used to modify the Nafion® membrane due to their hydrophilic nature, proton-conducting material, very low toxicity, low cost, and stability in a hydrogen/oxygen atmosphere. A tensile test, water uptake, methanol crossover, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to assess the capacity of nanocomposite membranes to function in a fuel cell. The modified Nafion® membrane had a higher water uptake and a lower water content angle than the commercial Nafion® 117 membrane, indicating that it has a greater impact on conductivity. Under strain rates of 40, 30, and 20 mm/min, the nanocomposite membranes demonstrated more stable thermal deterioration and higher mechanical strength, which offers tremendous promise for fuel-cell applications. When compared to 0.113 S/cm and 0.013 S/cm, respectively, of commercial Nafion® 117 and Nafion® ZrP membranes, the modified Nafion® membrane with ammonia sulphate acid had the highest proton conductivity of 7.891 S/cm. When tested using a direct single-cell methanol fuel cell, it also had the highest power density of 183 mW cm−2 which is better than commercial Nafion® 117 and Nafion® ZrP membranes.
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Sigwadi, Rudzani, and Fulufhelo Nemavhola. "Polyvinyl Alcohol/Nafion®–Zirconia Phosphate Nanocomposite Membranes for Polymer Electrolyte Membrane Fuel Cell Applications: Synthesis and Characterisation." Membranes 13, no. 12 (November 23, 2023): 887. http://dx.doi.org/10.3390/membranes13120887.
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PVA (polyvinyl alcohol)-ZrP (PVA/ZrP) and Nafion®/PVA-ZrP nanocomposite membranes were synthesised using the recasting method with glutaraldehyde (GA) as a crosslinking agent. The resulting nanocomposite membranes were characterised using a variety of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results of SEM revealed well-distributed zirconia phosphate (ZrP) within the membrane matrix, and the SEM images showed a uniform and dense membrane structure. Because ZrP nanoparticles are hydrophilic, the Nafion®/PVA-ZrP nanocomposite membrane had a higher water uptake of 53% at 80 °C and higher 0.19 S/cm proton conductivity at room temperature than the commercial Nafion® 117 membrane, which had only 34% and 0.113 S/cm, respectively. In comparison to commercial Nafion® 117 membranes, PVA-ZrP and Nafion®/PVA-ZrP nanocomposite membranes had a higher thermal stability and mechanical strength and lower methanol crossover due to the hydrophilic effect of PVA crosslinked with GA, which can make strong hydrogen bonds and cause an intense intramolecular interaction.
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Tawalbeh, Muhammad, Amani Al-Othman, Ahmad Ka'ki, Shima Mohamad, Amer Al-Jahran, Vishnu Unnikrishnan, Omid Zabihi, Quanxiang Li, Kamyar Shirvanimoghaddam, and Minoo Naebe. "High Temperature Studies of Graphene Nanoplatelets-MOFs Membranes for PEM Fuel Cells Applications." Key Engineering Materials 962 (October 12, 2023): 93–98. http://dx.doi.org/10.4028/p-3yscik.
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The wide applicability of proton exchange membrane fuel cells (PEMFCs) is hindered by their dependency on the Nafion membrane as a state-of-the-art electrolyte. Nafion membranes can only operate at relatively low temperatures, up to 80°C. Therefore, any application of the fuel cell above this temperature would cause the PEMFC to lose its proton conductivity and mechanical integrity. For this reason, the development of Nafion-free membranes for PEMFCs has been studied extensively through the corporation of several additives over polymer substrates. The charge transfer abilities of metal-organic frameworks (MOFs), among other properties, make them one of the possible additives. The objective of this work is to synthesize Nafion-free membranes based on graphene oxide, MOFs, ionic liquids, polyethylene glycol, and zirconium phosphate over PTTFE membrane as an alternative to Nafion membranes. The preliminary results gave proton conductivities in the range of 10-4 S/cm up to 150°C with graphene oxide MOF addition to all samples.
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Izquierdo-Gil, M. A., J. P. G. Villaluenga, S. Muñoz, and V. M. Barragán. "The Correlation between the Water Content and Electrolyte Permeability of Cation-Exchange Membranes." International Journal of Molecular Sciences 21, no. 16 (August 17, 2020): 5897. http://dx.doi.org/10.3390/ijms21165897.
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The salt permeability through three commercial cation-exchange membranes with different morphologies is investigated in aqueous NaCl solutions. Ion-exchange membranes (IEMs) find application in different processes such as electrodialysis, reverse osmosis, diffusion dialysis, membrane electrolysis, membrane fuel cells and ion exchange bioreactors. The aim of this paper is the experimental determination of the electrolyte permeability in the following membranes: MK-40 membrane, Nafion N324 membrane and Nafion 117 membrane. The latter is selected as being a reference membrane. The effect of an increase in the NaCl concentration in the solutions on membranes transport properties is analyzed. With regard to membranes sorption, a decrease in the water content was observed when the external electrolyte concentration is increased. Concerning permeation through the membranes, the salt permeability increased with concentration for the Nafion 117 membrane and remained nearly constant for the other two membranes. A close relation between the degree of liquid sorption by the membranes and the electrolyte permeability was observed.
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Ng, Wei Wuen, Hui San Thiam, Yean Ling Pang, Kok Chung Chong, and Soon Onn Lai. "A State-of-Art on the Development of Nafion-Based Membrane for Performance Improvement in Direct Methanol Fuel Cells." Membranes 12, no. 5 (May 10, 2022): 506. http://dx.doi.org/10.3390/membranes12050506.
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Nafion, a perfluorosulfonic acid proton exchange membrane (PEM), has been widely used in direct methanol fuel cells (DMFCs) to serve as a proton carrier, methanol barrier, and separator for the anode and cathode. A significant drawback of Nafion in DMFC applications is the high anode-to-cathode methanol fuel permeability that results in over 40% fuel waste. Therefore, the development of a new membrane with lower permeability while retaining the high proton conductivity and other inherent properties of Nafion is greatly desired. In light of these considerations, this paper discusses the research findings on developing Nafion-based membranes for DMFC. Several aspects of the DMFC membrane are also presented, including functional requirements, transport mechanisms, and preparation strategies. More importantly, the effect of the various modification approaches on the performance of the Nafion membrane is highlighted. These include the incorporation of inorganic fillers, carbon nanomaterials, ionic liquids, polymers, or other techniques. The feasibility of these membranes for DMFC applications is discussed critically in terms of transport phenomena-related characteristics such as proton conductivity and methanol permeability. Moreover, the current challenges and future prospects of Nafion-based membranes for DMFC are presented. This paper will serve as a resource for the DMFC research community, with the goal of improving the cost-effectiveness and performance of DMFC membranes.
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Sharma, Prem P., and Dukjoon Kim. "A Facile and Sustainable Enhancement of Anti-Oxidation Stability of Nafion Membrane." Membranes 12, no. 5 (May 13, 2022): 521. http://dx.doi.org/10.3390/membranes12050521.
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•OH radicals are the main cause of chemical degradation of Nafion membranes in fuel cell operation. Although the cerium ion (Ce3+/4+, Ce) is reported as an effective •OH radical quencher, its membrane application has critical limitations associated with the reduction of membrane proton conductivity and its leaking. In this study, the Ce-grafted graphitic carbon nitrides (g-C3N4) (CNCe) nano-particles are synthesized and embedded in Nafion membranes to prolong the •OH radical scavenging effect. The synthesis of CNCe nano-particles is evaluated by X-ray diffraction, energy dispersive X-ray analysis, and transmission electron microscopy. Compared with the pristine and Ce-blended Nafion membranes, the CNCe imbedded ones show tremendous improvement in long-term anti-oxidation stability. While the fluoride emission rates of Nafion are 0.0062 mg·cm−2·h−1 at the anode and 0.0034 mg·cm−2·h−1 at the cathode, those of Nafion/CNCe membranes are 0.0037 mg·cm−2·h−1 at the anode and 0.0023 mg·cm−2·h−1 at the cathode. The single cell test for Nafion/CNCe membranes at 80 °C and 50% relative humidity illustrates much better durability than those for Nafion and Nafion/Ce, indicating its superior scavenging effect on •OH radicals.
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Zizhou, Rumbidzai E., Ahmet Çay, E. Perrin Akçakoca Kumbasar, and C. Özgür Çolpan. "Production of poly(vinyl alcohol)/Nafion® nanofibers and their stability assessment for the use in direct methanol fuel cells." Journal of Industrial Textiles 50, no. 6 (April 23, 2019): 773–93. http://dx.doi.org/10.1177/1528083719844611.
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The aim of this study is to investigate the electrospinning of Nafion® nanofibers with poly(vinyl alcohol) (PVA) as a carrier polymer and to assess the thermal and chemical stability of resultant PVA/Nafion® nanofibers for the use in direct methanol fuel cells, in simulated conditions. Bead-free PVA/Nafion® nanofibers were produced using higher molecular weight PVA. Resultant PVA and PVA/Nafion® nanofibers were stabilized using two different methods which are BTCA crosslinking and thermal stabilization, followed by sulfonation of the PVA part. FT-IR analysis demonstrated that the membranes were stabilized and sulfonated successfully. Thermal, water, methanol and oxidative stability of the membranes were tested in addition to ion-exchange capacity. Morphological changes in the structure were analyzed using SEM analysis. Thermally stabilized PVA/Nafion® nanofibrous membrane was found to be stable against water, methanol and oxidative effects. The nanofibrous structure was well preserved after treatments, while the other membranes became a film-like material. Thermal stability of the PVA/Nafion® nanofibrous membrane was similar to that of commercial Nafion® 115 membrane up to 200℃.
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Xu, Guoxiao, Xinwei Dong, Bin Xue, Jianyou Huang, Junli Wu, and Weiwei Cai. "Recent Approaches to Achieve High Temperature Operation of Nafion Membranes." Energies 16, no. 4 (February 4, 2023): 1565. http://dx.doi.org/10.3390/en16041565.
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A proton exchange membrane fuel cell (PEMFC), as an efficient energy conversion device, has many advantages, such as high energy conversion efficiency and environmentally friendly zero emissions, and is expected to have great potential for addressing the uneven distribution of global green energy. As a core component, the performance of the proton exchange membrane (PEM) directly affects the overall output of the fuel cell system. At present, Nafion membranes with good, comprehensive properties are the most widely used commercial proton exchange membrane materials. However, Nafion membranes demonstrate a great inadaptability with an increase in operating temperatures, such as a rapid decay in proton conductivity. Therefore, enhancing the overall performance of Nafion membranes under high temperatures and low relative humidity (RH) has become an urgent problem. Although many efforts have been made to solve this problem, it is difficult to find the balance point between high-temperature conductivity and overall stability for researchers. In this paper, we summarize the recent approaches to improving the operating temperature of Nafion membranes from the following two perspectives: (1) using different materials for the modification of Nafion membranes, and (2) applying different modification methods to the Nafion membranes. Based on the structural and functional characteristics of Nafion, the non-destructive targeted filling of fillers and the efficient synergy of the two-phase region are two vital research directions for the preparation of high-performance composite membranes.
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Tian, Ai Hua, and Dong Hui Shen. "Modified Nafion Membranes by Catalytic Materials for Direct Methanol Fuel Cells Applications." Advanced Materials Research 684 (April 2013): 90–93. http://dx.doi.org/10.4028/www.scientific.net/amr.684.90.
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Sodium dodecyl sulfate/Pt composites and sodium dodecyl sulfate/Pd composites have been synthesized and used to modify the surface of Nafion membrane. Modified Nafion membranes have been characterized by Fourier transform infrared spectroscopy (FTIR). The properties of the modified membranes, in terms of their conductivity and the performance of the membrane electrode assembly (MEA) in the direct methanol fuel cells (DMFCs), have been analyzed and compared with those of the bare Nafion. It is found that the DMFC performance of the membranes modified by two kinds of catalytic materials are better than that of the bare Nafion when operated with 2.0 M methanol. The good conductivity and high cell performance makes the modified Nafion interesting candidates for DMFCs applications.
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Lutful Kabir, M. D., Subir Paul, Sang-June Choi, and Hee Jin Kim. "Improved Electrochemical and Mechanical Properties of Poly(vinylpyrrolidone)/Nafion® Membrane for Fuel Cell Applications." Journal of Nanoscience and Nanotechnology 20, no. 12 (December 1, 2020): 7793–99. http://dx.doi.org/10.1166/jnn.2020.18979.
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A novel blend of membranes made of Nafion® and poly(vinylpyrrolidone) (PVP) was prepared and characterized to investigate its applicability in proton exchange membrane fuel cells (PEMFCs). In addition to being effectively proton conductive, the membranes exhibited better mechanical strength, chemical stability, and adequate water retention ability, as well as ion exchange capacity comparable to that of cast Nafion® membrane. The data obtained from an electrochemical impedance spectroscopy (EIS) fitting of the fuel cells revealed the membrane electrode assemblies (MEAs) made of 0.5 wt.% PVP/Nafion® had lower ohmic and charge transfer resistance compared with that of the Nafion® membrane. The intermolecular interactions and morphology of these membranes were assessed using Fourier-transform infrared spectroscopy and field-emission scanning electron microscopy. The results of the performance curve indicate that the introduction of PVP as a modifier played a vital role in improving membrane performance. Accordingly, this solution-casted polymer electrolyte membrane with suitable PVP content offers a simple way to improve electrochemical, mechanical, and chemical properties, and thereby promises the prospect of use in low-temperature PEMFCs.
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Riku, Isamu, Keisuke Kawanishi, Ryoma Oka, and Koji Mimura. "On Computational Model of Nafion Membrane with Molecular Dynamic Method." Key Engineering Materials 775 (August 2018): 536–41. http://dx.doi.org/10.4028/www.scientific.net/kem.775.536.
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To clarify the effect of loading conditions on mechanical behavior of Nafion membrane, at first, molecular dynamic (MD) method is employed to constitute the computational models for Nafion membranes under periodic loading condition and for Nafion membrane under LJ flat wall loading condition. And then, a series of MD simulations are performed for Nafion membrane under different relative humidity (RH) circumstance. It is found that the computational results of the model under LJ flat wall loading condition gives a good agreement with the experimental result and is useful for the discussion on the localization of molecular chains at microscopic region.
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Xu, Guoxiao, Juan Zou, Zhu Guo, Jing Li, Liying Ma, Ying Li, and Weiwei Cai. "Bi-Functional Composting the Sulfonic Acid Based Proton Exchange Membrane for High Temperature Fuel Cell Application." Polymers 12, no. 5 (April 26, 2020): 1000. http://dx.doi.org/10.3390/polym12051000.
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Although sulfonic acid (SA)-based proton-exchange membranes (PEMs) dominate fuel cell applications at low temperature, while sulfonation on polymers would strongly decay the mechanical stability limit the applicable at elevated temperatures due to the strong dependence of proton conduction of SA on water. For the purpose of bifunctionally improving mechanical property and high-temperature performance, Nafion membrane, which is a commercial SA-based PEM, is composited with fabricated silica nanofibers with a three-dimensional network structure via electrospinning by considering the excellent water retention capacity of silica. The proton conductivity of the silica nanofiber–Nafion composite membrane at 110 °C is therefore almost doubled compared with that of a pristine Nafion membrane, while the mechanical stability of the composite Nafion membrane is enhanced by 44%. As a result, the fuel cell performance of the silica nanofiber-Nafion composite membrane measured at high temperature and low humidity is improved by 38%.
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Selim, Asmaa, Gábor Pál Szijjártó, Loránd Románszki, and András Tompos. "Development of WO3–Nafion Based Membranes for Enabling Higher Water Retention at Low Humidity and Enhancing PEMFC Performance at Intermediate Temperature Operation." Polymers 14, no. 12 (June 19, 2022): 2492. http://dx.doi.org/10.3390/polym14122492.
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The proton exchange membrane (PEM) represents a pivotal material and a key challenge in developing fuel cell science and hydrogen technology. Nafion is the most promising polymer which will lead to its commercialisation. Hybrid membranes of nanosized tungsten oxide (WO3) and Nafion were fabricated, characterised, and tested in a single cell. The incorporation of 10 wt% WO3 resulted in 21% higher water uptake, 11.7% lower swelling ratio, almost doubling the hydration degree, and 13% higher mechanical stability of the hybrid membrane compared to the Nafion XL. Compared to commercial Nafion XL, the rNF–WO-10 hybrid membrane showed an 8.8% and 20% increase in current density of the cell at 0.4 V operating at 80 and 95 °C with 1.89 and 2.29 A/cm2, respectively. The maximum power density has increased by 9% (0.76 W/cm2) and 19.9% (0.922 W/cm2) when operating at the same temperatures compared to the commercial Nafion XL membrane. Generally, considering the particular structure of Nafion XL, our Nafion-based membrane with 10 wt% WO3 (rNF–WO-10) is a suitable PEM with a comparable performance at different operating conditions.
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Liu, Shuangjie, Jialin Yu, Yongping Hao, Feng Gao, Mo Zhou, and Lijun Zhao. "Impact of SiO2 Modification on the Performance of Nafion Composite Membrane." International Journal of Polymer Science 2024 (January 8, 2024): 1–10. http://dx.doi.org/10.1155/2024/6309923.
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Using Nafion212 membrane and TEOS solution as raw materials, Nafion212/SiO2 composite membranes were prepared. In the in situ sol-gel reaction process, a series of Nafion/SiO2 composite membranes were prepared by varying the reaction temperature and reaction time. The effects of different modification schemes on Nafion/SiO2 composite membranes were studied using SEM, EDS, TEM, TGA, XRD, and mechanical tensile experiments, among other methods. The results show that Nafion/SiO2 composite membranes prepared at 3°C exhibit a well-separated phase structure and excellent water retention properties, with a water uptake of 29.23% and a swelling ratio of 24.25%. These membranes also demonstrate outstanding physical and chemical performance, with a maximum tensile stress of 13.6 MPa and an elongation at a break of 270%. At 110°C, the proton conductivity of the Nafion/SiO2 composite membrane reaches 0.172 S/cm, meeting the requirements for high-temperature proton exchange membrane fuel cells.
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Handayani, Sri, Eniya Listiani Dewi, Widodo Wahyu Purwanto, and Roekmijati W. Soemantojo. "Pengaruh aditif terhadap karakteristik membran elektrolit polieter-eter keton tersulfonasi untuk aplikasi sel bahan bakar metanol langsung." Jurnal Teknik Kimia Indonesia 6, no. 1 (October 2, 2018): 563. http://dx.doi.org/10.5614/jtki.2007.6.1.4.
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The influence of the additive on the characteristics of the sulfonated polyether-ether ketone electrolyte membrane for direct methanol fuel cell applicationsThe weakness of comercial membrane (Nafion-117) for the application of direct methanol fuel cell is highly methanol cross-over. It is decreasing the cell voltage. To minimize the methanol cross-over in a membrane, there are two methods can beproposed: the modification of conventional membrane structure (Nafion-117) and development of novel electrolyte membrane (and modified). PEEK can be used as one of alternatives for direct methanol fuel cell membranes. This PEEK polymer has the stability of chemistry mechanic and thermal. In order to increase ionic conductivity and to decrease methanol permeability. It is necessary to make the modification of sulfonated polyether-ether ketone (sPEEK) with adding higroscopic inorganic additives (SiO2 and H-zeolit). The type of additive which can increase ionic conductivity for sPEEK membrane is SiO2 (3 wt.%) 2 times, and decrease ionic conductivity 1,7 times for H-zeolite. Methanol permeability of membrane sPEEK with silica added increase 5 times and H-zeolite 2 times compared to sPEEK membrane without additive. Although composite membrane have increasing methanol permeability but that values are still lower than Nafion-117. Conclusion, the addition of SiO2 as additives has given best performance 0,09 S/cm ionic conductivity, 10-7 cm2/S methanol permeability dan 17 wt.% water swelling.Keywords: Additive, Direct Methanol Fuel Cell, Polyether-Ether Ketone, SiO2, H-ZeoliteAbstrakKelemahan membran komersial (Nafion-117) untuk aplikasi sel bahan bakar metanol langsung (direct methanol fuel cell) adalah methanol crossover yang tinggi, hal tersebut yang dapat menurunkan kinerja voltase sel secara keseluruhan. Dalam rangka mengurangi methanol crossover melalui membran, ada dua pendekatan yaitu modifikasi struktur membran konvensional (Nafion) atau pengembangan membran polimer elektrolit (dan modifikasi). Salah satu polimer aromatik yang menarik perhatian sebagai membran elektrolit pada aplikasi DMFC adalah polieter-eter keton (PEEK) karena polimer tersebut mempunyai kestabilan kimia, mekanik dan panas. Agar dapat meningkatkan konduktivitas ionik dan menurunkan permeabilitas metanol dilakukan modifikasi pada polieter-eter keton tersulfonasi (sPEEK) yaitu dengan menambahkan aditif anorganik yang bersifat higroskopik (SiO2 dan H-zeolit) Jenis aditif yang dapat meningkatkan konduktivitas ionik untuk membran elektrolit adalah SiO2 (3% berat) yaitu sebesar 2 kali, sedangkan H-zeolit menurunkan konduktivitas ionik sebesar 1,7 kali. Permeabilitas metanol membran sPEEK yang ditambahkan SiO2 naik hingga 5x sedangkan yang ditambahkan H-zeolit hanya 2 kali dari membran sPEEK tanpa aditif. Walaupun membran komposit meningkatkan permeabilitas metanol tetapi nilai tersebut masih dibawah membran Nafion-117. Jadi penambahan aditif yang baik dalam membran berbasis polieter-eter keton tersulfonasi adalah SiO2 yang mempunyai konduktivitas ionik 0,09 S/cm, permeabilitas metanol 10-7 cm2/S dan swelling air 17%.Kata kunci : Aditif, Polieter-Eter Keton, Sci Bahan Bakar Metanol Langsung, SiO,, H-Zeolit
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Sanjaya, Rochmad K., Juliandri Juliandri, Iman Rahayu, Nurul Ismillayli, and Dhony Hermanto. "CHEMICAL DEGRADATION OF NAFION MEMBRANES UNDER PEMFC AS INVESTIGATED BY DFT METHOD." Jurnal Sains Materi Indonesia 21, no. 2 (July 5, 2020): 49. http://dx.doi.org/10.17146/jsmi.2020.21.2.5582.
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CHEMICAL DEGRADATION OF NAFION MEMBRANES UNDER PEMFC AS INVESTIGATED BY DFT METHOD. An exsitu method has been developed to performance of Nafion's membrane in PEMFC (Proton Electrolyt Membrane Fuel Cells), caused by the chemical degradation of ·OH and ∙H radicals. The change of the chemical structure occurring during the degradation were primarily calculated of the relative energy of reactions by DFT (Density Functional Theory) method approach in the Gaussian software. This study aims to determine whether DFT method with functional B3LYP, PBEPBE, and B3PW91 and base sets 6-311++G can be used in determining the relative energy of a reaction and knowing the difference in role between ·OH and ∙H in the degradation process of the main chain Nafion with the final group are -CF2H, -CF=CF2 and -COOH. The three functionalities applied showed that the ·OH radical has more role than the ∙H radical in the degradation process of the Nafion main chain. In the -CF2H group was shown the relative energy value of reaction 2 is lower than reaction 5, in the -CF=CF2 group was shown the relative energy value of reaction 8* is lower than reaction 11 and in the -COOH group the relative energ value of reaction 14 is lower than reaction 16. By knowing the relative energy of the Nafion main chain degradation reaction with a certain final group and the role of certain radical compounds in the degradation process, the DFT method with functional B3LYP, PBEPBE and B3PW91 and base sets 6-311++G can recommend various modifications of the Nafion as a fuel cell membrane, particularly in increasing of membrane performance.
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Narayanamoorthy, B., B. Dineshkumar, and S. Balaji. "Clay Intercalated PVA-Nafion Bipolymer Matrix as Proton Conducting Nanocomposite Membrane for PEM Fuel Cells." Materials Science Forum 807 (November 2014): 161–68. http://dx.doi.org/10.4028/www.scientific.net/msf.807.161.
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The amino functionalized magnesium phyllosilicate clay (AC) intercalated over PVA-Nafion hybrid nanocomposite membranes were prepared by sol-gel method. The free standing membranes were obtained by solution recasting. The composition of clay materials such as AC and montmorillonite (MMT) was varied between 2-10 wt.% with respect to PVA-Nafion content. The molecular interactions and surface morphology of nanocomposite membranes were investigated by FT-IR and SEM analyses respectively. The thermal and mechanical stabilities of nanocomposite membranes were studied using TGA and Nanoindentation techniques. For 6 wt. % AC/PVA-Nafion, TGA results showed no appreciable mass change up to 380 °C and hardness calculated from nanoindentation studies was nearly 30 % higher than the other compositions. An improved conductivity was obtained for 6 wt. % AC/PVA-Nafion (1.4×10-2 S/cm) compared to pure Nafion (1.2×10-2 S/cm) and PVA-Nafion and MMT/PVA-Nafion composite membranes. From these studies, we observed that 6 wt. % AC/PVA-Nafion membrane possessed a good conductivity with higher thermal and mechanical stabilities.
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Mishra, Ananta Kumar, Seon Hyeong Bae, Nam Hoon Kim, Kin Tak Lau, and Joong Hee Lee. "Nafion-Peptized Laponite Clay Nanocomposite Membrane for PEMFC." Advanced Materials Research 410 (November 2011): 148–51. http://dx.doi.org/10.4028/www.scientific.net/amr.410.148.
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Nafion-clay nanocomposite membrane has been prepared by dispersing unmodified and acid activated Laponite XLS in Nafion 20% dispersion. The resulting membranes possess better proton conductivity and mechanical strength as compared to the virgin membrane. Acid activation of the nanoclay leads to thein-situgeneration of H3PO4by the hydrolysis of the peptizer present on the surface of the nanoclay. Thein-situgenerated H3PO4helps in improving all the technical properties of the nanocomposite including the water uptake and proton conductivity of the nanocomposite, containing acid activated clay compared to the nanocomposite, containing unmodified clay. The maximum proton conductivity of 270.2 mS/cm is achieved at 110 °C for the nanocomposite membrane containing 3% acid-activated Laponite compared to 136.2 mS/cm for the virgin Nafion. Keywords: Nafion, clay, nanocomposite, peptizer, polymer electrolyte membrane fuel cell (FEMFC), proton conductivity, membrane
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Patra, Sudeshna, Patrick Trinke, Boris Bensmann, and Richard Hanke-Rauschenbach. "Comparative Analysis of Degradation of Pristine Nafion and Catalyst Coated Membrane Subjected to Ex-Situ Fenton's Test Approach." ECS Meeting Abstracts MA2023-02, no. 39 (December 22, 2023): 1887. http://dx.doi.org/10.1149/ma2023-02391887mtgabs.
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Polyfluorinated sulfonic –acid ionomer membranes (e.g Nafion) are extensively used today as the benchmark materials for the electrolyte membrane in PEM water electrolysis. It is broadly accepted that the state of the health of PFSA membranes are adversely impacted by the chemical degradation occured during operation of PEMWE. The crossover gases on the catalytic surface generate Hydrogen Peroxide which is homolytically or in the presence of ferrous salts produce reactive oxygen species like hydroperoxyl (HO.) and hydroxyl (HO.) radicals. These radicals attack the ionomer subsequently leading to chain scission, unzipping and loss of functional groups and release of HF in the effluent water. Other than Fe3+, several transition metal ions Cu2+, Ni2+, Ti3+, Cu+, can poison the membrane significantly. The fact that membrane degradation is accelerated owing to introduction of ferrous ions is fervently implemented in ex-situ degradation tests (known as Fentons tests) to evaluate the durability of membrane materials. This work depicts a systematic investigation of degradation of pristine Nafion and catalyst coated Nafion membrane using a Fentons accelerated aging experiment. The durability of Nafion 117 and catalyst coated Nafion membrane with various counter ions against H2O2 was explored as a degradation factor of polymer electrolyte water electrolyser. Two distinct variations of the experiments were compared : (1) Nafion and CCM were dipped in only hydrogen peroxide solution, (2) Nafion and CCM were exposed to a solution containing ferrous ions and peroxide. Accelerated aging experiments were conducted over 3-7 days. The difference in degradation phenomena with and without Fe ions were evaluated in terms of the fluoride ion release. For both cases, to quantify the effect of water activity in Nafion and CCM chemical structure on both water diffusion and interfacial transport, pulse field gradient spin echo nuclear magnetic resonance (PFGSE-NMR) technique has been employed. Furthermore the equivalent weight of the Nafion and CCM can vary in presence of aforementioned chemical stressors which can be accurately quantitatively studied by confocal Raman spectroscopy. Morphological characteristic before and after aging test was also investigated. Role of H2O2 and ferous ion in mechanical behaviour of Nafion and CCM were also analyzed. The same experiment was repeated for different transition metal ions. This work sheds light on decomposition mechanism of Nafion and CCM in more detail.
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Li, Jian, Dario R. Dekel, and Viatcheslav Freger. "Preparation and Optimization of Novel Anisotropic Proton-Exchange Membranes with Enhanced through-Plane Conductivity." ECS Meeting Abstracts MA2023-02, no. 39 (December 22, 2023): 1899. http://dx.doi.org/10.1149/ma2023-02391899mtgabs.
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Maximizing through-plane (TP) conductivity, as opposed to in-plane (IP), is desired for proton exchange membranes (PEMs) in fuel cells, electrolysis and electrodialysis. Nafion, the benchmark PEM material, owes conductivity to randomly oriented ion-channels. Channel alignment in electrospun nanofibers was shown to enhance conductivity along the fibres by an order of magnitude, but it proved challenging to convert this to desired stable TP conductance. Another challenge is that orientation proves unstable and returns to random after nanofiber consolidation. Previously, we reported fabrication of electrospun nanofiber-based membrane with a stable anisotropic TP alignment of proton conducting channels prepared by co-spinning, buckling and fusion of Nafion and PVDF nanofibers (Odess, Li et al, ACS Appl Mat Interfaces, 2021), as shown in Figure 1. PVDF nanofibers serve as a mechanical reinforcement as well as a stabilizing component to safeguard Nafion TP alignment during annealing and swelling, akin to a solid template. However, the prepared 50% Nafion membrane still showed a TP conductivity slightly inferior to Nafion. In this report, we systematically optimized the Nafion content in the 50-80% range, as well as buckling and consolidation procedure and its temperature regime, to achieve a maximal and sustained conductance, exceeding that of pure Nafion. It was found that the TP proton conductivity of the membrane with 60% Nafion already exceeded that of Nafion 117 and further increased with Nafion content (Figure 1), with decrease in anisotropy (TP/IP conductance ratio). As another attractive feature, compared with Nafion 117, the TP conductivity of aligned membranes decreased less at lower humidity, i.e., was less sensitivity to dehydration, apparently due to better channel connectivity. Anisotropic structure and nanoscopic alignment were further confirmed by TEM and SAXS. The results demonstrate the potential of the new buckling approach for making novel nanofiber-based anisotropic membranes with significantly improved performance in electromembrane applications. Figure 1
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Danwanichakul, Panu, and Pongchayont Sirikhajornnam. "An Investigation of Chitosan-Grafted-Poly(vinyl alcohol) as an Electrolyte Membrane." Journal of Chemistry 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/642871.
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The membrane of chitosan-grafted-poly(vinyl alcohol)/poly(vinyl alcohol) (CS-g-PVA/PVA) was investigated along with chitosan (CS), PVA, CS/PVA, and Nafion 117 membranes for transport properties of water and methanol, mechanical properties, and ionic conductivity. The ionic conductivity,σ, of the crosslinked CS-g-PVA/PVA membrane was about 4.37 mS cm−1and the methanol permeability,PS, was1.8×10−7 cm2s−1. These gave the selectivity,σ/PS, of 23.95 mS·s·cm−3compared with 16.35 mS·s·cm−3of Nafion 117 membrane. The conductivity of the crosslinked CS-g-PVA/PVA membrane was greater than others including Nafion 117 when the membranes were saturated with methanol solution of which concentration was greater than 20%. This fact and that the mechanical properties of the wet crosslinked CS-g-PVA/PVA membrane were comparable to those of other membranes made it a promising material to be used as an electrolyte membrane in a direct methanol fuel cell.
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Segale, Mayetu E., Touhami Mokrani, and Rudzani A. Sigwadi. "Synthesis and Characterization of Enhanced Proton-Conducting Nafion<sup>® </sup>117- Silica Composite Membranes for Fuel Cell Applications." Journal of Nano Research 82 (April 8, 2024): 95–116. http://dx.doi.org/10.4028/p-3lgu0l.
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Nafion®/silica nanocomposite membranes were prepared by impregnation method from Nafion® 117 and sol-gel pre-synthesized n-octadecyl-trimethoxy silane (C18TMS) coated silica nanoparticles. The scanning electron microscope (SEM) of pristine silica particles displayed monodispersed nanospheres with diameters ranging from 150-350 nm; while Brunauer-Emmett-Teller (BET) analysis presented 760 m2/g BET surface area, a micropore-mesopore bimodal distribution of micropore systems with respective pore volume at 14.6 Å and 17.0 Å (2.01 x 10-3 cm3/g.Å), as well as the prolific mesopores centered at 29.5 Å (5.64 x 10-2 cm3/g.Å). Characterization of Nafion® 117 based membranes on SEM, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and x-ray diffraction (XRD), and tensile stress exhibited varying surface morphology with silica loadings, structural interaction between membrane support and the ion exchanger, thermal stabilities (up to 330 °C), crystalline nature, and reasonable mechanical stability of nanocomposite membranes. The maximum water uptake (44.8 %) and proton conductivity of (1.14 x10-2 S/cm) were obtained on low Nafion®/SiO2 (5%) loaded membrane. While both composite membranes displayed the improved reduction in methanol permeability, 2.43x10-07 cm2/s at 80 °C was obtained with high Nafion®/SiO2 (10%) loading. Improved water uptake and proton conductivity substantiate the high ion exchange capacity (IEC) of 1.81 meq.g-1 when compared to IEC of 0.93 meq.g-1 [pristine Nafion®] and 1.46 meq.g-1 [Nafion®/SiO2 (10%)]. The increase in IEC value may be due to the high acid functionalization of additional sulfonic acid groups surrounded by hydrophilic segments of nanosilica, which improves the properties of the membrane. The high proton conductivity coupled with great water retention capabilities indicated that the Nafion®/SiO2 nanocomposite membranes could be utilized as proton exchange membranes for medium temperature methanol fuel cells. Keywords: Fuel cells; nanocomposite membrane; SiO2 nanofillers; methanol permeability; ion exchange capacity
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Christwardana, Marcelinus, Satrio Kuntolaksono, Athanasia Amanda Septevani, and H. Hadiyanto. "Starch – carrageenan based low-cost membrane permeability characteristic and its application for yeast microbial fuel cells." International Journal of Renewable Energy Development 13, no. 2 (February 17, 2024): 303–14. http://dx.doi.org/10.61435/ijred.2024.59160.
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Microbial fuel cells (MFCs) are an innovative method that generates sustainable electricity by exploiting the metabolic processes of microorganisms. The membrane that divides the anode and cathode chambers is an important component of MFCs. Commercially available membranes, such as Nafion, are both costly, not sustainable, and harmful to the environment. In this study, a low-cost alternative membrane for MFCs based on a starch-carrageenan blend (SCB-LCM) was synthesized. The SCB-LCM membrane was created by combining starch and carrageenan and demonstrated a high dehydration rate of 98.87 % over six hours. SEM analysis revealed a smooth surface morphology with no pores on the membrane surface. The performance of SCB-LCM membrane-based MFCs was evaluated and compared to that of other membranes, including Nafion 117 and Nafion 212. All membranes tested over 25 hours lost significant weight, with SCB-LCM losing the least. The maximum power density (MPD) of the SCB-LCM MFCs was 15.77 ± 4.34 mW/m2, indicating comparable performance to commercial membranes. Moreover, the cost-to-power ratio for MFCs employing SCB-LCM was the lowest (0.03 USD.m2/mW) when compared to other membranes, indicating that SCB-LCM might be a viable and cost-effective alternative to Nafion in MFCs. These SCB-LCM findings lay the groundwork for future research into low-cost and sustainable membrane for MFC technologies.
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Zhao, Yang, Bing Xu, Bu Lei Xu, Ling Ke Yu, and Dao Heng Sun. "Study on the Performance of Ionic Polymer-Metal Composites of Various Fabrication Technique." Advanced Materials Research 815 (October 2013): 650–54. http://dx.doi.org/10.4028/www.scientific.net/amr.815.650.
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onic Polymer Metal Composites (IPMC) is a new kind of electro-active smart material that has many advantages including bending actuation, large displacement, low weight, low driven voltage, low power consumption, flexibility etc. The mechanical characteristic of IPMC is related to ionic polymer membrane, such as thickness, roughening, cation type and so on. In this paper, the actuation principle of IPMC and fabrication technique of NafionTM membrane is presented. The performance of IPMC with Nafion membrane pre-treatment, different cation type and thickness are investigated. Experiment results showed that the fabrication process of ionic polymer membrane Nafion change can improve the performance of IPMC effectively.
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Nemavhola, F., and R. Sigwadi. "Prediction of Hyperelastic Material Properties of Nafion117 and Nafion/ZrO2 Nano-Composite Membrane." International Journal of Automotive and Mechanical Engineering 16, no. 2 (July 4, 2019): 6524–40. http://dx.doi.org/10.15282/ijame.16.2.2019.5.0492.
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This paper presents constitutive laws suitable for the prediction of mechanical behaviour of nano-composite membrane compared with the commercial membrane Nafion®117. The uniaxial tensile data of commercial Nafion®117 and Nafion®/ Zr-150 nano-composite membrane utilised for fitting hyperelastic models was determined experimentally. Several material models on mechanical behaviour of nano-composite and commercial Nafion® 117 membrane material was fitted to determined accuracy. In order to observe yield and fracture behaviour, the com-mercial Nafion®117 and Nafion®/ Zr-150 nano-composite membranes were loaded in uniaxial direction at a constant strain rate. To obtain the optimal material constants form six different material models considered in this study, the OriginLab® version 9 was used and the Leven-berg-Marquardt (M) optimization logarithm. Hyperplastic material models including Mooney-Rivlin, Yeoh, Ogden, Humphrey, Martins and Veronda-Westmann were selected to use in an inverse method to fit the experimental uniaxial data of nano-composite material. The hyper-plastic material parameters could then be used to simulate material behaviour of nano mem-brane using finite element analysis (FEA) technique. The procedure discussed in this paper could be used to accurately determine the constitutive parameters of various constitutive models of Polymer Nafion presented.
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Lehmann, Michelle L., Ethan C. Self, Tomonori Saito, and Guang Yang. "Composite Membrane for Sodium Polysulfide Hybrid Redox Flow Batteries." Membranes 13, no. 8 (July 27, 2023): 700. http://dx.doi.org/10.3390/membranes13080700.
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Non-aqueous redox flow batteries (NARFBs) using earth-abundant materials, such as sodium and sulfur, are promising long-duration energy storage technologies. NARFBs utilize organic solvents, which enable higher operating voltages and potentially higher energy densities compared with their aqueous counterparts. Despite exciting progress throughout the past decade, the lack of low-cost membranes with adequate ionic conductivity and selectivity remains as one of the major bottlenecks of NARFBs. Here, we developed a composite membrane composed of a thin (<25 µm) Na+-Nafion coating on a porous polypropylene scaffold. The composite membrane significantly improves the electrochemical stability of Na+-Nafion against sodium metal, exhibiting stable Na symmetric cell performance for over 2300 h, while Na+-Nafion shorted by 445 h. Additionally, the composite membrane demonstrates a higher room temperature storage modulus than the porous polypropylene scaffold and Na+-Nafion separately while maintaining high Na+ conductivity (0.24 mS/cm at 20 °C). Our method shows that a composite membrane utilizing Na+-Nafion is a promising approach for sodium-based hybrid redox flow batteries.
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Gagliardi, Gabriele G., Carlotta Cosentini, and Domenico Borello. "An efficient composite membrane to improve the performance of PEM reversible fuel cells." E3S Web of Conferences 334 (2022): 04018. http://dx.doi.org/10.1051/e3sconf/202233404018.
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The aim of this study is to develop composite Nafion/GO membranes, varying GO loading, to be used in a Unitized reversible fuel cell comparing its performance with the baseline Nafion. Water uptake, ion exchange capacity (IEC), tensile strength, and SEM (scanning electron microscope) analysis are discussed. The SEM analysis revealed how the GO is homogeneously disposed into the Nafion matrix. The addition of GO improves the membrane tensile strength while reducing the elongation ratio. Water uptake, IEC enhance with the increasing of GO content. Regarding fuel cell mode, the performance is analysed using a polarization curve on a MEA with an effective area of 9 cm2. The composite membrane demonstrated higher mechanical strength, enhanced water uptake so higher performance in fuel cell mode. Despite the power absorbed from the electrolysis is higher when using a composite membrane, the beneficial effect in FC mode resulted in a slightly higher round trip efficiency. The GO-Nafion membrane was not able to maintain its performance with increasing the operating time, so potentially leading to a lower lifetime than the Nafion bare.
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Chen, Taipu, Bo Lv, Shucheng Sun, Jinkai Hao, and Zhigang Shao. "Novel Nafion/Graphitic Carbon Nitride Nanosheets Composite Membrane for Steam Electrolysis at 110 °C." Membranes 13, no. 3 (March 7, 2023): 308. http://dx.doi.org/10.3390/membranes13030308.
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Hydrogen is expected to have an important role in future energy systems; however, further research is required to ensure the commercial viability of hydrogen generation. Proton exchange membrane steam electrolysis above 100 °C has attracted significant research interest owing to its high electrolytic efficiency and the potential to reduce the use of electrical energy through waste heat utilization. This study developed a novel composite membrane fabricated from graphitic carbon nitride (g-C3N4) and Nafion and applied it to steam electrolysis with excellent results. g-C3N4 is uniformly dispersed among the non−homogeneous functionalized particles of the polymer, and it improves the thermostability of the membranes. The amino and imino active sites on the nanosheet surface enhance the proton conductivity. In ultrapure water at 90 °C, the proton conductivity of the Nafion/0.4 wt.% g-C3N4 membrane is 287.71 mS cm−1. Above 100 °C, the modified membranes still exhibit high conductivity, and no sudden decreases in conductivity were observed. The Nafion/g-C3N4 membranes exhibit excellent performance when utilized as a steam electrolyzer. Compared with that of previous studies, this approach achieves better electrolytic behavior with a relatively low catalyst loading. Steam electrolysis using a Nafion/0.4 wt.% g-C3N4 membranes achieves a current density of 2260 mA cm−2 at 2 V, which is approximately 69% higher than the current density achieved using pure Nafion membranes under the same conditions.
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Bébin, Philippe, and Hervé Galiano. "Proton Exchange Membrane Development and Processing for Fuel Cell Application." Materials Science Forum 539-543 (March 2007): 1327–31. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.1327.
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The development of new proton exchange membranes for PEMFC has to be related to the membrane processing as it can change drastically the final properties of the material. Indeed, for the same material, a membrane prepared by a solvent-casting process has a lower lifetime than an extruded one. The proton conduction of the membrane can also be dependent on the membrane processing, especially when some removable plasticizers are used to perform the membrane extrusion. Some residual porosity, left in the material after removing the plasticizer, is suspected to enhance the proton conduction of the film. Fuel cell experiments have shown that extruded sulfonated polysulfone membrane can give the same performance as a Nafion® reference membrane whereas the proton conductivity of PSUs is twenty times lower than the Nafion® one. Additional improvements of the membrane properties can also be expected by adding some proton conductive fillers to the organic polymer. This approach enhances the proton conductivity of sulfonated polysulfone to values similar to Nafion®. On the other hand, when Nafion® is used as a matrix for the proton conductive fillers, a very significant improvement of fuel cell performance is obtained.
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Madhav, Dharmjeet, Changyuan Shao, Jorben Mus, Frank Buysschaert, and Veerle Vandeginste. "The Effect of Salty Environments on the Degradation Behavior and Mechanical Properties of Nafion Membranes." Energies 16, no. 5 (February 26, 2023): 2256. http://dx.doi.org/10.3390/en16052256.
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The application of proton-exchange membrane fuel cells (PEMFCs) in maritime transportation is currently in the spotlight due to stringent emissions regulations and the establishment of a carbon trading system. However, salt in the marine environment can accelerate the degradation of proton-exchange membranes (PEM), which are the core component of PEMFCs. In this study, the effect of the NaCl concentration and temperature on the degradation of Nafion, the benchmark PEMFC membrane, was analyzed ex situ by accelerated degradation using Fenton’s test. The membrane properties were studied by mass change, fluoride ion emission, FTIR spectroscopy, and tensile test. The results showed that the degradation of Nafion membranes increased with the increase in temperature and NaCl concentration. Further studies revealed that Nafion produces C=O bonds during the degradation process. Additionally, it was found that sodium ions replace hydrogen ions in degraded Nafion fragments based on analysis of the weight change, and the rate of substitution increases with increasing temperature. A better understanding of the degradation behavior of Nafion in salty environments will lead to the advanced manufacturing of PEM for applications of PEMFCs in maritime transportation.
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Jiang, Fengjing, and Rui Xue. "Ion-Selective Membranes Fabricated Using Finely Controlled Swelling of Non-Ionic Fluoropolymer for Redox Flow Batteries." Batteries 9, no. 11 (November 6, 2023): 545. http://dx.doi.org/10.3390/batteries9110545.
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Ion-selective membranes based on non-ionic polymers are promising for redox flow batteries due to their superior chemical stability and low cost. In this work, a poly(vinylidene fluoride) (PVDF) ion-selective membrane is successfully prepared using a solvent-controlled swelling method, where Nafion is used as a channel-forming promoter. The influences of Nafion on the channel formation of the membranes are studied. The results indicate that the addition of Nafion resin can greatly promote the formation of ion-conducting channels in the PVDF matrix. The obtained membranes show well-controlled proton conductivity and proton/vanadium selectivity. A battery test on a vanadium redox flow single cell is successfully performed. The energy efficiency of the cell equipped with the PVDF-based ion-selective membrane reaches 81.7% at a current density of 60 mA cm−2 and possesses excellent cycling stability and suppressed self-discharge after modification with Nafion.
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Hirai, Tomoyasu, Tamio Seko, Wataru Higashiguchi, Syuji Fujii, and Yoshinobu Nakamura. "(Digital Presentation) Characterization of Molecular Aggregation State in Deteriorated Nafion Membrane on the Basis of X-Ray Diffraction Measurement." ECS Meeting Abstracts MA2022-02, no. 39 (October 9, 2022): 1421. http://dx.doi.org/10.1149/ma2022-02391421mtgabs.
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Nafion is widely utilized as key polymer for proton electrolyte fuel cells owing to their high chemical, mechanical, and proton-conducting properties. The molecular aggregation state in Nafion films strongly affects the performance in the fuel cells. During operation process in fuel cells, peroxide derivatives such as H2O2 is generated and the chemical species deteriorates Nafion membrane, leading to a decreasing of performance of the fuel cells. The detail deterioration process including local structure, however, does not well-understand. In this work, we evaluate the local molecular aggregation state in deteriorated Nafion using microbeam wide X-ray diffraction (WAXD) measurements. Figure 1a shows WAXD line profile of before and after deterioration of Nafion membranes. The diffraction peaks were observed in ranging from 11 to 12 nm-1, which could be assigned to crystalline and amorphous structure in Nafion. The ratio of crystalline peak in deteriorated Nafion was more striking than that of initial Nafion membrane. This phenomenon might be explained following two mechanism. ① Polymer chains in amorphous domain were disconnected and were removed from the membrane. ② Polymer chains were disconnected and molecular motion of lower molecular weight is activated, leading to a formation of new crystalline domain caused by aggregation of lower molecular weight polymer chains. It is anticipated that above mechanisms occurs individually or at the same time. Though the dominant mechanism is still not clear, we can conclude that deterioration in Nafion starts from amorphous domain. To evaluate local molecular aggregation state in deteriorated Nafion, microbeams with size of 50 μm and 7 μm were utilized for WAXD measurements. Figure 1b and c show variation of ratio in crystalline domain as function of strain. The ratio of the crystalline domain in deteriorated Nafion was more striking than that of untreated Nafion. The ratio was constant when 50 μm beam was used, but not the case in 7 μm beam. This indicates that deterioration of Nafion membrane occurs 7 to 50 μm scale. The detail will be discussed in my presentation. Figure 1
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Peterson, Vanessa K., Cormac Corr, Gordon J. Kearley, Roderick Boswell, and Zunbeltz Izaola. "High Water Diffusivity in Low Hydration Plasma-Polymerised Proton Exchange Membranes." Materials Science Forum 654-656 (June 2010): 2871–74. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2871.
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This paper compares proton diffusion through plasma-polymerised proton-exchange membranes (PEMs) produced using traditional wet-chemical methods (Nafion®) and those produced using plasma-polymerisation. Using quasielastic neutron scattering and a simple model of proton motion we find the measured diffusion-rate of protons in the plasma-polymerised material and Nafion® is the same (within 1 standard error) even though the plasma-polymerised membrane has 80 % less water than the Nafion®. We attribute this result to the highly cross-linked structure of the plasma-polymerised membrane.