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1.
质子交换膜对钒氧化还原液流电池性能的影响   总被引:10,自引:0,他引:10  
采用溶液接枝聚合法制备了一种新型的质子交换膜PVDF-g-PSSA, 测定了PVDF-g-PSSA膜、Nafion 117 膜和PE01均相膜的离子交换能力和电导率, 并分别研究了以这3种膜为隔膜的钒电池的电化学性能. 实验结果表明, PVDF-g-PSSA膜具有优良的质子电导率和离子交换能力, 室温下其离子交换能力和质子电导率分别为1.13 mmol/g和3.22×10-2 S/cm, 在不同的充放电电流密度下, 以PVDF-g-PSSA膜为隔膜的钒电池的库仑效率和能量效率明显高于Nafion 117膜和PE01均相膜为隔膜的钒电池; PVDF-g-PSSA膜阻钒离子的渗透性能与PE01均相膜基本一致, 都明显优于Nafion 117膜的阻钒离子渗透能力.  相似文献   

2.
In order to reduce the cost of membrane used in vanadium redox flow battery (VRB) system while keeping its chemical stability, Nafion/sulfonated poly(ether ether ketone) (SPEEK) layered composite membrane (N/S membrane) consisting of a thin layer of recast Nafion membrane and a layer of SPEEK membrane were prepared by chemical crosslink the sulfonic acid groups of different ionomer membranes. Scanning electron microscopy (SEM) and IR spectra analysis of the membrane showed that Nafion layer was successfully deposited on the SPEEK membrane surface and an integral layered membrane structure was formed. The area resistance and permeability of vanadium ions of membrane were also measured. It was found that N/S membrane have a very low permeability of vanadium ions accompanied by a little higher area resistance compared with Nafion membrane. As a result, the VRB single cell with N/S membrane exhibited higher coulombic efficiency and lower voltage efficiency compared with VRB single cell with Nafion membrane. Although N/S membrane delivered relatively lower energy efficiency compared with Nafion membrane, its good chemical stability and low cost make it a suitable substitute for Nafion membrane used in VRB system.  相似文献   

3.
以含3,3'-二烯丙基双酚 A 结构单元的聚醚醚酮为基膜材料, 通过自由基加成反应在取代基上引入磺酸基团, 合成侧链型磺化聚醚醚酮(SPEEK)质子交换膜. 用傅里叶变换红外(FTIR)光谱、 核磁共振氢谱(1H NMR)、 热重分析(TG)和扫描电子显微镜(SEM)等方法对 SPEEK 的结构进行表征. 实验结果表明, 巯基丙磺酸被接枝在聚醚醚酮侧基上, SPEEK 膜具有明显的亲水疏水微相分离形貌, 磺酸基团相互聚集形成离子通道. SPEEK 膜离子交换容量为 2.12 mmol/g, 钒离子渗透率为 1.54×10-6 cm2/min, 低于Nafion117 膜的钒离子渗透率, 阻钒能力优于 Nafion117 膜. 以 SPEEK-4 膜组装电池的自放电时间约为130 h, 长于 Nafion117 膜的 66 h. 电池充放电循环 50 次, SPEEK-4 膜的库仑效率、 电压效率和能量效率没有明显降低, 显示出良好的稳定性.  相似文献   

4.
以双酚芴为结构单元合成双酚型聚醚醚酮聚合物,聚醚醚酮经浓硫酸磺化在双酚芴结构单元中引入磺化基团制备出聚醚醚酮质子交换膜(SF-PEEK)。 用傅里叶变换红外光谱(FTIR)、核磁共振氢谱(1H NMR)、热重分析(TG)、原子力显微镜(AFM)和扫描电子显微镜(SEM)等方法对聚醚醚酮质子交换膜的结构进行表征。 结果表明,磺酸基团被成功地在聚醚醚酮侧基上,SF-PEEK膜具有明显的亲水疏水微相分离形貌,磺酸基团相互聚集成形成离子通道。 SF-PEEK膜离子交换容量(IEC)达到1.97 mmol/g时,其电导率达到4.15×10-2 S/cm,略低于Nafion117膜的5.67×10-2 S/cm,但其钒离子渗透率仅为Nafion117膜的20.1%,表现出极好的离子选择性。 在钒流电池测试中,SF-PEEK膜在不同电流密度下库伦效率均高于Nafion117膜,其中IEC为1.97 mmol/g的SF80-PEEK608(80为SF的物质的量分数,608为60 ℃反应8 h)库伦效率在电流密度为40 mA/cm2时达到最大值80.9%,高于Nafion117膜的78.8%。 在自放电测试中,以SF80-PEEK608膜组装的电池的自放电时间为90 h,高于Nafion117膜的57 h。  相似文献   

5.
Proton exchange membrane (PEM) is a key component of vanadium redox flow battery (VRB), and its proton/vanadium selectivity plays an important role in the performance of a VRB single cell. Commercially available perfluorosulfonic acid (Nafion) membranes have been widely used due to their excellent proton conductivity and favorable chemical resistance. However, the large pore size micelle channels formed by the pendant sulfonic acid groups lead to the excessive penetration of vanadium ions, which seriously affects the coulombic efficiency (CE) of the single cell and accelerates the self-discharge rate of the battery. Additionally, the expensive cost of Nafion is also an important reason to limit its large-scale application. In this paper, the dense and low-cost hydrocarbon polymer polybenzimidazole (PBI) is used as the matrix material of the PEM, which is doped with phosphotungstic acid (PWA) to acquire excellent proton conductivity, and the intrinsic high resistance of PBI for vanadium ions is helpful to obtain high proton/vanadium selectivity. Considering the enormous water solubility of PWA and its easy leaching from membrane, organic polymer nano-Kevlar fibers (NKFs) are utilized as the anchoring agent of PWA, which achieves good anchoring effect and solves the problem of the poor compatibility between inorganic anchoring agent and the polymer matrix. The formation of PWA functionalized NKFs was characterized by scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy. The anchoring stability of NKFs for PWA was evaluated by UV-Vis spectroscopy. The characterizations including water uptake, swelling ratio, ion exchange capacity, proton conductivity, vanadium ion permeability and ion selectivity were performed to evaluate the basic properties of the membranes. At the same time, the charge-discharge, self-discharge and cycle performance of single cell assembled with the composite membrane and recast Nafion were tested at various current densities from 40 to 100 mA∙cm-2. Simple tuning for the filling amount of NKFs@PWA gives the composite membrane superior ion selectivity including an optimal value of 3.26 × 105 S∙min∙cm-3, which is 8.5 times higher than that of recast Nafion (0.34 × 105 S∙min∙cm-3). As a result, the VRB single cell assembled with the composite membrane exhibits higher CE and significantly lower self-discharge rate compared with recast Nafion. Typically, the CE of the VRB based on PBI-(NKFs@PWA)-22.5% membrane is 97.31% at 100 mA∙cm-2 while the value of recast Nafion is only 90.28%. The open circuit voltage (VOC) holding time above 0.8 V of the single cell assembled with the composite membrane is 95 h, which is about 2.4 times as long as that of recast Nafion-based VRB. The utilization of PBI as a separator for VRB can effectively suppress the penetration of vanadium ions, achieve higher proton/vanadium selectivity and superior battery performance as well as reduce the cost of the PEM, which will play an active role in the promotion of VRB applications.  相似文献   

6.
To improve the performance of Nafion membrane as a separator in vanadium redox battery (VRB) system, a Nafion/TiO2 hybrid membrane was fabricated by a hydrothermal method. The primary properties of this hybrid membrane were measured and compared with the Nafion membrane. The Nafion/TiO2 hybrid membrane has a dramatic reduction in crossover of vanadium ions compared with the Nafion membrane. The results of scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray diffraction of the hybrid membrane revealed that the TiO2 phase was formed in the bulk of the prepared membrane. Cell tests identified that the VRB with the Nafion/TiO2 hybrid membrane presented a higher coulombic efficiency (CE) and energy efficiency (EE), and a lower self-discharge rate compared with that of the Nafion system. The CE and EE of the VRB with the hybrid membrane were 88.8% and 71.5% at 60 mA cm−2, respectively, while those of the VRB with Nafion membrane were 86.3% and 69.7% at the same current density. Furthermore, cycling tests indicated that the Nafion/TiO2 hybrid membrane can be applied in VRB system.  相似文献   

7.
本文采用壳聚糖-磷钨酸层对Nafion膜表面分别进行单面和双面修饰改性,研究了修饰模式对Nafion膜钒离子渗透率、电导率及离子选择性的影响. 结果表明,单面、双面修饰改性均会使Nafion膜的钒离子渗透率显著降低,最高降幅分别达到89.9% (单面修饰) 和92.7% (双面修饰);单面、双面修饰改性均会使Nafion膜的电导率下降,但存在明显差异,在相同修饰厚度条件下,双面修饰改性对Nafion膜电导率的影响比单面修饰改性更小。因此,双面修饰复合膜展示出了比单面修饰复合膜更高的离子选择性,并且在修饰层厚度为17 μm时达到最大值(1.12×105 S•min•cm-3). 基于优化的双面修饰Nafion膜的全钒液流电池,在充放电流密度30 mA•cm-2 时,库伦效率和能量效率分别达到93.5%和 80.7%, 并且在测试时间内展示出良好的循环稳定性.  相似文献   

8.
A sulfonated polyimide (SPI)/TiO2 composite membrane was fabricated by a blend way to improve its performance in vanadium redox flow battery (VRB). Both EDS and XRD results verify the successful preparation of the SPI/TiO2 composite membrane. The surface SEM image shows its homogeneous structure. TG analysis identifies its thermal stability. The SPI/TiO2 composite membrane possesses much lower permeability of VO2+ ions (2.02?×?10?7 cm2 min?1) and favorable proton conductivity (3.12?×?10?2 S cm?1). The VRB single cell with SPI/TiO2 composite membrane shows higher coulombic efficiency (93.80–98.00 %) and energy efficiency (83.20–67.61 %) at the current density ranged from 20 to 80 mA cm?2 compared with that with Nafion 117 membrane. And the operational stability of the as-prepared composite membrane is good after 50 times of cycling tests. Therefore, the low-cost SPI/TiO2 composite membrane with excellent battery performance exhibits a great potential for application in VRB.  相似文献   

9.
Aiming to develop a suitable ion exchange membrane for vanadium redox flow battery (VRB), a new kind of imidazolium salt type anion exchange membrane based on the copolymer of N‐vinylimidazole and 2,2,2‐trifluoroethyl methacrylate has been prepared. The membrane is characterized by means of water uptake, ion‐exchange capacity, ionic conductivity, and thermal stability. Furthermore, a VRB with this membrane is assembled, and the performance of such VRB is evaluated. The permeability experiments show that this membrane has reasonable low permeability of vanadium ions. The coulombic efficiency (CE) and energy efficiency (EE) of VRB with the synthesized membrane are 99.5% and 75.0%, whereas the CE and EE of the VRB with Nafion® 117 membrane are 82.6% and 72.6%, respectively. The synthesized membrane shows good chemical stability in VRB via more than 4000 cycles test. Therefore, this membrane shows good applicable potential in VRB. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

10.
通过溶液流延法制备了磺化聚醚醚酮/锂皂石(SPEEK/Lap)复合膜, 对其物理化学性质、 机械性能、 化学稳定性及单电池性能进行了测试. 在SPEEK基质中引入的Lap有效改善了复合膜的质子传导率、 溶胀率和机械性能. 当Lap添加量(质量分数)从0.2%增到1.5%时, 复合膜的质子传导率随之增加(19.9~23.6 mS/cm). SPEEK/Lap-0.2复合膜的自放电时间为57.2 h, 是Nafion 117膜的2.4倍和纯SPEEK膜的1.5倍. 在80 mA/cm 2电流密度下, SPEEK/Lap-0.2复合膜的电压效率(VE, 86.5%)和能量效率(EE, 84.0%)明显高于Nafion 117膜(VE: 83.8%, EE: 80.7%)和纯SPEEK膜(VE: 81.4%, EE: 78.9%). 同时, SPEEK/Lap-0.2复合膜经100次充放电循环测试后具有良好的循环稳定性和结构稳定性.  相似文献   

11.
As an alternative to Nafion® ion exchange membrane, an inexpensive commercially-available Radel® polymer was sulfonated, fabricated into a thin membrane, and evaluated for its performance in a vanadium redox flow battery (VRFB). The sulfonated Radel (S-Radel) membrane showed almost an order of magnitude lower permeability of VO2+ ions (2.07 × 10?7 cm2/min), compared to Nafion 117 (1.29 × 10?6 cm2/min), resulting in better coulombic efficiency (~ 98% vs. 95% at 50 mA/cm2) and lower capacity loss per cycle. Even though the S-Radel membrane had a slightly higher membrane resistance, the energy efficiency of the VRFB with the S-Radel membrane was comparable to that of Nafion because of its better coulombic efficiency resulting from the lower vanadium ion crossover. The S-Radel membrane exhibited good performance up to 40 cycles, but a decline in performance at later cycles was observed, likely as a result of membrane degradation.  相似文献   

12.
To develop a novel and low-cost membrane as a separator of vanadium redox flow battery, sulfonated poly(phthalazinone ether sulfone) (SPPES) was prepared by sulfonating PPES with fuming sulfuric acid. By testing the sulfonation degree, intrinsic viscosity, and solubility of SPPES, the results showed that sulfonated polymers had higher intrinsic viscosities and excellent solubility in most polar solvents. IR analysis revealed that the –SO3H group was successfully attached to SPPES backbone. DSC and TG results showed that SPPES exhibited higher T g than that of PPES, and T d at the first weight loss of SPPES was about 300?°C. The SPPES membrane (SP-02) showed a dramatic reduction in crossover of vanadium ions across the membrane compared with that of the Nafion membrane. Cell tests identified that VRB with the SPPES membrane exhibited a lower self-discharge rate, higher coulombic efficiency (92.82%), and higher energy efficiency (67.58%) compared with the Nafion system. Furthermore, cycling tests indicated that the single cell with SPPES membrane exhibited a stable performance during 100?cycles.  相似文献   

13.
Three kinds of sulfonated poly(ether ether ketone) (SPEEK)/nano oxide (Al2O3, SiO2, and TiO2) composite membranes are fabricated for vanadium redox flow battery (VRFB) application. The composite membranes with 5 wt% of Al2O3, SiO2, and TiO2 (S/A-5 %, S/S-5 %, and S/T-5 %) exhibit excellent cell performance in VRFB. Incorporation of nano oxides (Al2O3, SiO2, and TiO2) in SPEEK membrane improves in aspect of thermal, mechanical, and chemical stabilities due to the hydrogen bonds’ interaction between SPEEK matrix and nano oxides. The energy efficiencies (EEs) of composite membranes are higher than that of Nafion 117 membrane, owing to the good balance between proton conductivity and vanadium ion permeability. The discharge–capacity retentions of composite membranes also overwhelm that of Nafion 117 membrane after 200 cycles, indicating their good stability in VRFB system. These low-cost SPEEK/nano oxide composite membranes exhibit great potential for the application in VRFB.  相似文献   

14.
聚偏氟乙烯-Nafion共混膜的制备及阻醇质子导电性能研究   总被引:7,自引:0,他引:7  
直接甲醇燃料电池 (Directmethanolfuelcell,MDFC)以高效、清洁和燃料储运方便等优点成为一类极具发展潜力的新型动力源 .但目前DMFC中普通使用的全氟磺酸膜 (如NafionTM 系列膜 )阻醇性能太差 ,导致大量甲醇从阳极穿过膜直接透到阴极 ,造成燃料的浪费和电池整体性能的下降 .据文献报道 ,即使甲醇浓度低到 1mol L ,也有近40 %的醇透过膜 .缺乏高性能的阻醇质子导电聚合物电解质膜是制约DMFC发展的瓶颈之一 .已有一些研究人员致力于新型膜材料的开发 ,如有人研制了聚苯并咪唑膜[1] 及各种掺杂…  相似文献   

15.
The performance of Si-PWA/PVA nanocomposite membrane in vanadium redox-flow battery (VRB) is reported. Structurally, the membrane consisted of a dispersion of sub-micron-sized silica immobilized phosphotungstic acid (Si-PWA) inorganic ion-exchanging phase in the continuous phase of cross-linked poly(vinyl alcohol) (PVA). SEM micrographs indicated the defect-free top surface of membrane with similar morphology of Nafion-115. Good ion selectivity and availability of ion-exchangeable sites were observed as indicated by higher transport number (0.89) and ion-exchange capacity (IEC) (1.20 meq g?1), respectively. Oxidative stability of the membrane was good in vanadium ion species (V4+, V3+, and V2+) but its stability in V5+ solution and Fenton’s reagent was slightly lower than Nafion-115. Vanadium ion permeability (0.69 × 10?7 cm min?1) of Si-PWA/PVA membrane was significantly lower than Nafion-115. Suitability for VRB with Si-PWA/PVA membrane was assessed from open-circuit voltage (OCV) decay which was lower compared to Nafion-115. Single-cell VRB with Si-PWA/PVA membrane exhibited lower voltage during charge and higher during discharge with excellent cyclic stability compared to VRB with Nafion-115.  相似文献   

16.
本文报道了采用浓硫酸作为磺化剂,成功合成了不同磺化度下的聚醚醚酮(PEEK)膜,并深入研究了磺化条件包括磺化时间和磺化剂的用量对所获薄膜性能的影响,获得了在不同磺化度(DS)下SPPEK膜的离子交换容,含水率,机械性能,质子电导率等参数,特别测定了在全钒液流电池工作条件下钒离子(Ⅳ)渗透率,首次为该类液流储能电池使用价廉质优的质子交换膜提供了基础实验数据。室温条件下的实验结果如下:1)磺化12小时后,膜的磺化度46%,含水量为28%,钒离子(Ⅳ)选择性最佳(钒离子渗透率为1.2×10-7 cm2/min-1,是Nafion117 (2.9×10-6 cm2/min-1)的1/24),其质子电导率只有0.02 S/cm;2)磺化96小时其磺化度达79%的膜,质子电导率达0.16 S/cm,是Nafion117 (0.10S/cm) 的1.6倍, 但其机械性能最差;3)与Nafion117膜相比,磺化在36到48小时的SPPEK膜其机械力学性能好,薄膜的钒离子渗透率、离子交换容IEC、质子导电率和含水率高,且对钒离子的选择性佳,尤其价格仅为Nafion膜的1/13,是理想的Nafion膜的代替物,可望直接应用于全钒氧化还原液流(VRB)电池中。本文还讨论了磺化时间和不同磺化剂量对膜的性质的影响。  相似文献   

17.
Ion exchange membranes play a key role in all vanadium redox flow batteries (VRFBs). The mostly available commercial membrane for VRFBs is Nafion. However, its disadvantages, such as high cost and severe vanadium‐ion permeation, become obstacles for large‐scale energy storage. It is thus crucial to develop an efficient membrane with low permeability of vanadium ions and low cost to promote commercial applications of VRFBs. In this study, graphene oxide (GO) has been employed as an additive to the Nafion 212 matrix and a composite membrane named rN212/GO obtained. The thickness of rN212/GO has been reduced to only 41 μm (compared with 50 μm Nafion 212), which indicates directly lower cost. Meanwhile, rN212/GO shows lower permeability of vanadium ions and area‐specific resistance compared to the Nafion 212 membrane due to the abundant oxygen‐containing functional groups of GO additives. The VRFB cells with the rN212/GO membrane show higher Coulombic efficiencies and lower capacity decay than those of VRFB cells with the Nafion 212 membrane. Therefore, the cost‐effective rN212/GO composite membrane is a promising alternative to suppress migration of vanadium ions across the membrane to set up VRFB cells with better performances.  相似文献   

18.
Sulfonated polyimide (SPI) and ZrO2 are blended to prepare a series of novel SPI/ZrO2 composite membranes for vanadium redox flow battery (VRFB) application. Results of atomic force microscopy and X‐ray diffraction reveal that ZrO2 is successfully composited with SPI. All SPI/ZrO2 membranes possess high proton conductivity (2.96–3.72 × 10?2 S cm?1) and low VO2+ permeability (2.18–4.04 × 10?7 cm2 min?1). SPI/ZrO2‐15% membrane is determined as the optimum one on account of its higher proton selectivity and improved chemical stability. The VRFB with SPI/ZrO2‐15% membrane presents higher coulombic efficiency and energy efficiency than that with Nafion 117 membrane at the current density, which ranged from 20 to 80 mA cm?2. Cycling tests indicate that the SPI/ZrO2‐15% membrane has good operation stability in the VRFB system. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

19.
In order to prevent the vanadium crossover and preferential water transfer in all-vanadium redox flow battery (VRFB), three methods – electrolyte soaking, oxidation polymerisation and Electrodeposition, were used to modify Nafion 117 membranes using pyrrole. The surface of the modified membranes was uniform and even, and the membranes were characterised in terms of morphology, membrane area resistance, vanadium permeability and water transfer property. The properties of all the modified membranes were improved greatly. The membranes modified by Electrodeposition showed a best combination of the membrane resistance, vanadium permeability and water transfer property, the experimental results showed that the V(IV) ion permeability of polypyrrole modified Nafion membranes by Electrodeposition at the conditions of 0.025 mA cm−2 and 0 °C for 60 min reduced more than 5 times from 2.87 × 10−6 cm2 min−1 to 5.0 × 10−7cm2 min−1, and the water transfer property decreased more than 3 times from 0.72 ml/72 h cm2 to 0.22 ml/72 h cm2. All above properties made the modified Nafion membranes more applicative in the VRFB system. This paper also reported other methods for Nafion membrane modification and the influences of the deposition conditions on the properties of the membrane selectivity and water transfer.  相似文献   

20.
改性聚偏氟乙烯接枝共混聚苯乙烯磺酸膜的制备与性能   总被引:1,自引:0,他引:1  
将苯乙烯添加到溶有原硅酸钠改性的聚偏氟乙烯(PVDF)N-甲基吡咯烷酮溶液中, 以过氧化苯甲酰(BPO)作引发剂, 苯乙烯直接接枝到原硅酸钠改性的PVDF链上, 成膜后磺化制备了聚偏氟乙烯接枝苯乙烯(PVDF-g-PSSA)膜. 采用傅立叶变换红外光谱(FT-IR)、扫描电镜(SEM)、能量扩散X射线(EDX)和多功能材料实验机表征了膜的结构、形貌及硫和硅的分布、机械强度、溶胀度, 使用阻抗分析和气相色谱仪研究了苯乙烯含量(w)对PVDF-g-PSSA膜的质子导电性能和阻醇性能的影响. 结果表明, 苯乙烯加入后, 原硅酸钠改性的PVDF与苯乙烯进行接枝共聚反应, 苯乙烯磺化反应不只是在膜表面进行, 同时渗入到膜中进行, 机械性能得到了改善. 质子电导率(σ)随苯乙烯质量分数的提高而升高. Na4SiO4为8%和苯乙烯为20%的PVDF-g-PSSA膜, 在25 ℃时溶胀度仅为20.4%, 甲醇透过系数在10-7 cm2·s-1数量级上, 比Nafion115膜的低一个数量级. 该膜具有较高的选择性, 在直接甲醇燃料电池中具有良好的应用前景.  相似文献   

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