scholarly journals High Proton Selectivity Sulfonated Polyimides Ion Exchange Membranes for Vanadium Flow Batteries

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1315 ◽  
Author(s):  
Qi Chen ◽  
Liming Ding ◽  
Lihua Wang ◽  
Haijun Yang ◽  
Xinhai Yu

High proton selectivity is the ultimate aim for the ion exchange membranes (IEMs). In this study, two kinds of sulfonated polyimides (SPI)—non-fluorinated and fluorine-containing polyimide—with about 40% sulfonation degree were synthesized by one-step high temperature polymerization. High proton selectivity IEMs were prepared and applied in vanadium flow batteries (VFB). The chemical structures, physicochemical properties and single cell performance of these membranes were characterized. The results indicate that high molecular weight of SPIs can guarantee the simultaneous achievement of good mechanical and oxidative stability for IEMs. Meanwhile, the proton selectivity of SPI membrane is five times higher than that of Nafion115 membranes due to the introduction of fluorocarbon groups. Consequently, the single cell assembled with SPI membranes exhibits excellent energy efficiency up to 84.8% at a current density of 100 mA·cm−2, which is 4.6% higher than Nafion115. In addition, the capacity retention is great after 500 charge–discharge cycles. All results demonstrate that fluorinated SPI ion exchange membrane has a bright prospect in new energy field.

2019 ◽  
Vol 7 (10) ◽  
pp. 5794-5802 ◽  
Author(s):  
Xiujun Yue ◽  
Qian He ◽  
Hee-Dae Lim ◽  
Ping Liu

A hierarchically structured composite ion exchange membrane is developed to solve the trade-off between conductivity and selectivity.


2015 ◽  
Vol 3 (33) ◽  
pp. 16948-16952 ◽  
Author(s):  
Daishuang Zhang ◽  
Xiaoming Yan ◽  
Gaohong He ◽  
Le Zhang ◽  
Xinhong Liu ◽  
...  

We proposed an integrally thin skinned asymmetric anion exchange membrane with sufficiently low ion exchange capacity for vanadium flow batteries (VFBs), and this work provides new insights into the design, fabrication and commercialization of ion exchange membranes for VFBs.


Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
AHM Golam Hyder ◽  
Brian A. Morales ◽  
Malynda A. Cappelle ◽  
Stephen J. Percival ◽  
Leo J. Small ◽  
...  

Electrodialysis (ED) desalination performance of different conventional and laboratory-scale ion exchange membranes (IEMs) has been evaluated by many researchers, but most of these studies used their own sets of experimental parameters such as feed solution compositions and concentrations, superficial velocities of the process streams (diluate, concentrate, and electrode rinse), applied electrical voltages, and types of IEMs. Thus, direct comparison of ED desalination performance of different IEMs is virtually impossible. While the use of different conventional IEMs in ED has been reported, the use of bioinspired ion exchange membrane has not been reported yet. The goal of this study was to evaluate the ED desalination performance differences between novel laboratory‑scale bioinspired IEM and conventional IEMs by determining (i) limiting current density, (ii) current density, (iii) current efficiency, (iv) salinity reduction in diluate stream, (v) normalized specific energy consumption, and (vi) water flux by osmosis as a function of (a) initial concentration of NaCl feed solution (diluate and concentrate streams), (b) superficial velocity of feed solution, and (c) applied stack voltage per cell-pair of membranes. A laboratory‑scale single stage batch-recycle electrodialysis experimental apparatus was assembled with five cell‑pairs of IEMs with an active cross-sectional area of 7.84 cm2. In this study, seven combinations of IEMs (commercial and laboratory-made) were compared: (i) Neosepta AMX/CMX, (ii) PCA PCSA/PCSK, (iii) Fujifilm Type 1 AEM/CEM, (iv) SUEZ AR204SZRA/CR67HMR, (v) Ralex AMH-PES/CMH-PES, (vi) Neosepta AMX/Bare Polycarbonate membrane (Polycarb), and (vii) Neosepta AMX/Sandia novel bioinspired cation exchange membrane (SandiaCEM). ED desalination performance with the Sandia novel bioinspired cation exchange membrane (SandiaCEM) was found to be competitive with commercial Neosepta CMX cation exchange membrane.


Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 346 ◽  
Author(s):  
Stanislav Melnikov ◽  
Denis Bondarev ◽  
Elena Nosova ◽  
Ekaterina Melnikova ◽  
Victor Zabolotskiy

Bilayer ion-exchange membranes are mainly used for separating single and multiply charged ions. It is well known that in membranes in which the layers have different charges of the ionogenic groups of the matrix, the limiting current decreases, and the water splitting reaction accelerates in comparison with monolayer (isotropic) ion-exchange membranes. We study samples of bilayer ion-exchange membranes with very thin cation-exchange layers deposited on an anion-exchange membrane-substrate in this work. It was revealed that in bilayer membranes, the limiting current’s value is determined by the properties of a thin surface film (modifying layer). A linear regularity of the dependence of the non-equilibrium effective rate constant of the water-splitting reaction on the resistance of the bipolar region, which is valid for both bilayer and bipolar membranes, has been revealed. It is shown that the introduction of the catalyst significantly reduces the water-splitting voltage, but reduces the selectivity of the membrane. It is possible to regulate the fluxes of salt ions and water splitting products (hydrogen and hydroxyl ions) by changing the current density. Such an ability makes it possible to conduct a controlled process of desalting electrolytes with simultaneous pH adjustment.


Author(s):  
Eliška Stránská ◽  
Kristýna Weinertová ◽  
David Neděla ◽  
Jan Křivčík

This article focuses on the preparation of the heterogeneous ion exchange membrane with a special surface structure made with three types of knitted fabric. The special surface structure of ion exchange membranes can be useful for the intensification of mass transfer processes in electrodialysis.Three types of structured ion exchange membranes were prepared together with a membrane with a flat surface to compare the influence of geometrical structures on the behaviour of ion exchange membrane properties. Electrochemical, mechanical and physical properties were determined. Structured membranes exhibited comparable electrochemical and physical properties to the flat ion exchange membrane. Some transport parameters were measured in an electrodialysis stack with two concentrations of solution. Two electrodialysis stacks with different sizes of active area were used for comparison. Improving efficiency and mass flux was not confirmed. It was not demonstrated that structured IEMs were not better than IEMs with the flat surface.


2021 ◽  
Vol 51 (1) ◽  
pp. 21-46
Author(s):  
Klaus-Dieter Kreuer ◽  
Andreas Münchinger

This review discusses selective and fast transport of ionic species (ions and their associates) through systems as diverse as ion-conducting transmembrane proteins and ion exchange membranes (IEMs) in aqueous environments, with special emphasis on the role of electrostatics, specific chemical interactions, and morphology (steric effects). Contrary to the current doctrine, we suggest that properly balanced ion-coordinating interactions are more important than steric effects for selective ion transport in biological systems. Steric effects are more relevant to the selectivity of ionic transport through IEMs. As a general rule, decreased hydration leads to higher selectivity but also to lower transport rate. Near-perfect selectivity is achieved by ion-conducting channels in which unhydrated ions transfer through extremely short hydrophobic passages separating aqueous environments. In IEMs, ionic species practically keep their hydration shell and their transport is sterically constrained by the width of aqueous pathways. We discuss the trade-off between selectivity and transport rates and make suggestions for choosing, optimizing, or developing membranes for technological applications such as vanadium-redox-flow batteries.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yi-Chiang Huang ◽  
Ruei-Hong Tai ◽  
Hsu-Feng Lee ◽  
Po-Hsun Wang ◽  
Ram Gopal ◽  
...  

A series of sterically hindered, sulfonated, poly(arylene ether) polymers were synthesized by nucleophilic polycondensation reaction using 4,4′′′′-difluoro-3,3′′′′-bistrifluoromethyl-2′′,3′′,5′′,6′′-tetraphenyl-[1,1′;4′,1′′;4′′,1′′′;4′′′,1′′′′]-pentaphenyl and 4,4′-biphenol and were prepared through postpolymerization sulfonation. The chemical structures were confirmed by1H NMR. Subsequent to sulfonation, solvent-casting membranes were provided ion exchange capacity (IEC) values ranging from 0.39 to 2.90 mmol/g. Proton conductivities of membranes ranged from 143 to 228 mS/cm at 80°C under fully humidified conditions which were higher than that of Nafion 117. The membrane also exhibited considerably dimension stability, oxidative stability, and hydrolytic stability. The microphase structure was investigated by transmission electron microscopy (TEM) and the ionic aggregation of sulfonic acid groups exhibited spherical ionic clusters with well-developed phase separated morphology. The results indicated that the membranes are promising candidates for application as proton exchange membranes. This investigation demonstrates introducing multiphenylated moieties to create a high free volume polymer that provides dimensionally stable and high proton conductivity membranes.


2020 ◽  
Vol 20 (11) ◽  
pp. 6797-6801
Author(s):  
Tae Yang Son ◽  
Jun Seong Yun ◽  
Kihyun Kim ◽  
Sang Yong Nam

This study describes the use of poly(phenylene oxide) polymer-based ion-exchange polymers, polystyrene-based ion-exchange particles and a porous support for fabricating bipolar membranes and the results of an assessment of the applicability of these materials to water splitting. In order to achieve good mechanical as well as good ion-exchange properties, bipolar membranes were prepared by laminating poly(phenylene oxide) and polystyrene based ion-exchange membranes with a sulfonated polystyrene-block-(ethylene-ran-butylene)-block-polystyrene) (S-SEBS) modified interface. PE pore-supported ion-exchange membranes were also used as bipolar membranes. The tensile strength was 13.21 MPa for the bipolar membrane which utilized only a cation/anion-exchange membrane. When ion-exchange nanoparticles were introduced for high efficiency, a reduction in the tensile strength to 6.81 MPa was observed. At the same time, bipolar membrane in the form of a composite membrane using PE support exhibited the best tensile strength of 32.41 MPa. To confirm the water-splitting performance, an important factor for a bipolar membrane, pH changes over a period of 20 min were also studied. During water slitting using CA-P-PE-BPM, the pH at the CEM part and the AEM part changed from 5.4 to 4.18 and from 5.4 to 5.63, respectively.


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