Bipolar membranes in forward bias region for fuel cell reactors

Three bipolar membranes, two home-made composed of commercial cation (DuPont) and anion (FuMA-Tech) exchange membranes (called Nafion/FT-FAA and Nafion/FT-FAS) and a commercial one, BP-1 from FuMA-Tech, were investigated in order to characterize their suitability to use in a H₂/O₂ fuel cell intended to produce hydrogen peroxide on the cathode instead of water. The Nafion/FT-FAA and Nafion/FT-FAS membranes were prepared using a hot-pressing method. The optimal hot-pressing conditions were determined by measuring the ionic conductivity of the membranes. The latter was observed to depend on the relative humidity of the bipolar membrane. Of the studied bipolar membranes, Nafion/FT-FAA showed the best performance. The transport number of protons measured in a concentration cell was observed to depend on the direction of the proton diffusion flux through these membranes so that transport numbers of ca. unity were obtained when the cation exchange side faced the solution with higher proton concentration. In the opposite case, when the higher concentration faced anion exchange side, the transport number of proton was clearly lower, indicating the usefulness of the bipolar membranes for hydrogen peroxide production in the fuel cell.     

CHITOSAN-BASED FUEL CELL MEMBRANES

Chitosan complex membranes are prepared and characterized at room temperature. They are expected to be used as proton exchange membranes. The studied membranes are cross-linked membranes with sulfuric acid; salt-complexed membranes with lithium nitrate; cross-linked and salt-complexed membranes; plasticized and salt-complexed membranes; cross-linked, plasticized, and salt-complexed membranes; and doped membranes with sulfuric acid. A fixed amount of ethylene carbonate is used as plasticizer. It is found that the ion exchange capacity and hydrogen gas permeability of all membranes is better than that of Nafion membranes. However, their proton conductivities are worse than Nafion membranes. It can be stated that ethylene carbonate does not improve conductivity. An optimum amount of lithium nitrate salt can enhance conductivity. The formation of a sulfate group in cross-linked membranes is necessary for proton conduction. The proton conductivities of 4%cross-linked and 50%LiNO₃ membrane before and after acid doping are (3.11±0.40) × 10^-2 and (6.64±0.11) × 10^-2 S cm^-1, respectively. That of Nafion is (8.02±1.19) × 10^-2 S cm^-1.     

磺化含酚酞侧基聚芳醚酮/氧化石墨烯复合质子交换膜的性能

采用共混制备了一系列磺化含酚酞侧基聚芳醚酮(SPEK-C)/氧化石墨烯(GO)复合质子交换膜,系统地研究了GO含量对复合膜性能的影响。结果表明,GO含量对膜的离子交换容量、稳定性、质子电导率和甲醇渗透率等有重要影响。复合膜质子电导率随GO含量增加而提高,GO含量为2%和5%的复合膜在80℃下质子电导率均在10^-1 S·cm^-1以上。80℃下,GO含量为5%的复合膜甲醇渗透率为6.69×10^-7 cm²·s^-1,低于同温度下复合前SPEK-C膜1个数量级。复合后膜的化学稳定性增强,离子交换容量和含水率均有提高,相对选择性明显增大,最高达SPEK-C的18.2倍。     

全钒液流电池用非氟咪唑型阴离子交换膜的制备

在全钒电池(VFB)用离子交换膜中,阴离子交换膜以其钒离子渗透率低这一主要优势受到了广泛的关注。以N-溴代丁二酰亚胺(NBS)为溴化试剂,2,2'-偶氮二异丁腈(AIBN)为引发剂,对聚苯醚(PPO)的苄甲基溴化;以N-正丁基咪唑为功能化试剂,制备了一种非氟咪唑型聚苯醚阴离子交换膜。研究了不同N-正丁基咪唑功能化程度的阴离子交换膜的离子传导率、离子交换容量(IEC)、含水率、钒离子传递系数等性能,并与N-甲基咪唑功能化的阴离子交换膜做了对比。结果显示,N-正丁基咪唑功能化聚苯醚阴离子交换膜的钒离子传递系数为4.8×10^-9 cm·min^-1,60℃时离子传导率为10.8 mS·cm^-1,且化学稳定性及力学性能优异,具有在钒电池中应用的潜力。     

Water transport in ion exchange membranes

Water transport across ion exchange membranes has been studied experimentally. Water transference numbers were obtained from streaming potential measurements for cation and anion exchange membranes. At low salt concentration the water transference number reaches a limiting value which for the cation exchange membranes seems to be closely correlated with the cation—water friction in infinite dilute solutions.The observed water transference number for a given anion exchange membrane does not seem to be much dependent on the type of coion even at concentrations where the membrane is no longer perfectly permselective.     

Boron removal by ion exchange membranes

Boron removal from aqueous solution was studied through Neosepta-AHA membrane by Donnan dialysis (DD) method as a function of concentration, pH, conduct time, membrane structure and effect of accompanying ions. The feasibility of the system was examined and the highest boron removal was obtained when the pH of the feed phase was 9.5. On the other hand, it was determined that reverse flow transition was accelerated by counter ions and HCO₃⁻ ion was found to be more effective than Cl⁻ and SO₄⁻² ions. It was determined that obtained results of AHA membrane was compared with Neosepta AFN and AMH membranes and the flow rate of boron through Neosepta AHA, AFN and AMH anion exchange membranes were found to be between 3.10⁻⁸−3232.10⁻⁸ mmol cm⁻² s⁻¹ depending on concentration of feed and receiver phases, pH as well as counter ion properties. The order for recovery of boron for membranes was found to be as AFN>AMH>AHA. It could be concluded that the DD method is an appropriate method for boron removal from aqueous solution when an appropriate counter anion was chosen at suitable pH value.     

基于PVDF薄膜辐照接枝制备质子交换膜

含氟磺酸型质子交换膜是一类具有高热稳定性、化学稳定性及良好力学性能的离子交换膜,具有极其广阔的应用前景。采用⁶⁰Co辐照接枝技术,在聚偏氟乙烯（PVDF）基膜上产生自由基聚合位点,进而接枝对苯乙烯磺酰氯单体,经过一定条件酸碱处理得到一种新型偏氟磺酸型质子交换膜。并对其进行红外分析,结果显示PVDF膜上成功接枝上了对苯乙烯磺酰氯单体;定量研究了在相同辐照总剂量、不同剂量率条件下,所得质子交换膜的质子传导率、吸水率及离子交换容量与接枝率的关系,结果表明：当剂量率为40 Gy·min^-1时,所得质子交换膜接枝率为52.7%,吸水率为36.85%,80℃时质子传导率达到136 mS·cm^-1,离子交换容量为1.274 mmol·g^-1。     

Nitric acid and sodium hydroxide generation by electrodialysis using bipolar membranes

An electrodialysis process with bipolar membranes was used to generate HNO3 and NaOH from NaNO3 which can be found in industrial waste waters. The current efficiency of this process is limited by proton leakage through the anion exchange membrane (AEM), co-ion leakage through bipolar membranes (BPM) and water transport through the ion exchange membranes. Three cell configurations using three or two compartment cells with different anion or cation exchange membranes (CEM) in stack series were used and compared. Electrodialysis with three compartments gives the best current efficiencies for nitric acid and sodium hydroxide production from sodium nitrate.     

不同羧酸根含量对双官能团聚降冰片烯质子交换膜性能影响的分子动力学模拟

基于Material Studio（MS）软件平台,构建了含有磺酸根和羧酸根双功能化基团的新型聚降冰片烯类质子交换膜模型。通过改变3种结构单元NBSC、DCNM以及DCNM-N的不同配比,探究了不同羧酸根含量对质子交换膜性能的影响,同时分析了质子交换膜的微观结构以及H₂O和H₃O⁺等小分子的输运特性。计算结果显示,H₂O和H₃O⁺的均方位移和扩散系数随着羧酸根含量的增加而逐渐减小。在298 K条件下,3种质子交换膜的质子传导率分别为22.75、46.14、56.77 mS·cm^-1。表明随着羧酸根个数的增加,质子传导率不断增大,但增幅先增大后减小。     

A novel anion exchange membranes with fluorinated poly（aryl ether oxadiazole）s ionomer for all-vanadium redox flow battery

离子交换膜的钒离子渗透是制约全钒液流电池效率的因素之一。制备了一种新型的、低钒离子渗透的氟化聚芳醚阴离子交换膜。以六氟双酚A、四甲基联苯二酚、含氟单体合成了多氟聚噁二唑芳醚。以N-溴代丁二酰亚胺（NBS）为溴化试剂,过氧化二苯甲酰（BPO）为引发剂,将多氟聚噁二唑芳醚上的甲基进行溴化、功能化得到多氟聚噁二唑芳醚阴离子交换膜（QFOAEM）。研究了该膜的钒离子渗透率、离子传导率、吸水率、溶胀度和离子交换容量（IEC）等性能。研究结果表明：QFOAEM的钒离子渗透率为1.1×10^-8cm²·min^-1,低于Nafion117的3.8×10^-7cm²·min^-1,具有在全钒液流电池中应用的潜力。     

膜在微生物燃料电池分隔材料中应用的研究进展

分隔材料是微生物燃料电池(MFC)中质子从阳极向阴极传递的必经通道,具有非常重要的作用,目前广泛采用的MFC分隔材料是各种类型的膜材料.本文综述了近年来膜在MFC分隔材料中应用的研究现状,分析了质子膜、阳离子交换膜、阴离子交换膜、双极膜、微滤膜、超滤膜、多孔滤料等不同膜材料用作MFC分隔材料时的特性、离子传递机制及其优缺点,并对微生物燃料电池分隔材料未来发展的方向和面临的挑战进行了展望.     

Influence of chemical compositions on the properties of random and multiblock sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes

The influence of chemical compositions on the properties of sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes was studied. First, we synthesized three different series of random SPAES copolymers using three kinds of hydrophobic monomers, including 4,4′‐dihydroxyldiphenylether, 2,6‐dihydroxynaphthalene (DHN), and 4,4′‐hexafluoroisopropylidenediphenol (6F‐BPA) to investigate effects of hydrophobic components on the properties of SPAES membranes as proton‐exchange membranes. Random SPAES copolymers with 6F‐BPA showed the highest proton conductivity while random SPAES copolymers with DHN displayed the lowest methanol permeability among the three random copolymers. Subsequently, we synthesized multiblock SPAES using the DHN as a hydrophobic monomer and studied the effect of the length of hydrophilic segments in the multiblock SPAES copolymers on membrane performance. The results indicated that longer hydrophilic segments in the copolymers led to higher water uptake, proton conductivity, and proton/methanol selectivity of membranes even at low humidity. In addition, the morphology studies (AFM and SAXS measurements) of membranes suggested that multiblock copolymers with long hydrophilic segments resulted in developed phase separation in membranes, and ionic clusters formed more easily, thus improving the membrane performance. Therefore, both the kinds of hydrophobic monomers and the length of hydrophilic segments in SPAES copolymers would influence the membranes performance as proton‐exchange membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

燃料电池用碱性阴离子交换膜的研究进展

碱性阴离子交换膜(AAEM)是碱性阴离子交换膜燃料电池(AAEMFC)的核心部件,起到阻隔阴阳两极和传导OH-的双重作用,其性能好坏直接影响到AAEMFC的性能和使用寿命。从膜的结构和制备方法分类,综述了碱性阴离子交换膜燃料电池用有机-无机杂化膜、掺杂型膜及均相膜的特性和研究现状。     

磺化聚醚醚酮掺杂叔铵盐类离子液体复合膜的制备及离子液体与Pt/C催化剂的相容性

采用中和法制备了两种叔铵盐类离子液体[（CH₃CH₂）₃NH⁺][HSO₄^-]（简称TEAS）及[（CH₃CH₂）₃NH⁺][H₂PO₄^-]（简称TEAP）,傅里叶红外光谱图表明制备的离子液体为TEAS及TEAP。并将制备的叔铵盐类离子液体掺杂到不同磺化度的磺化聚醚醚酮（简称SPEEK）中,通过溶液浇铸法制备了SPEEK/IL复合膜,对复合膜进行了差示扫描量热（DSC）表征,测试了复合膜中离子液体的流失率及其与Pt/C催化剂的循环伏安（CV）及氧还原（ORR）曲线。SPEEK掺杂叔铵盐类离子液体后,由于叔铵盐离子液体以化学力与SPEEK网状结构中的磺酸基结合,导致复合膜的热稳定性下降,但同时也降低了复合膜中的离子液体流失率。CV及ORR曲线表明,Pt/C催化剂与叔铵盐离子液体电化学窗口相差较小,氧还原活性降低少,两者相容性较好。此类复合膜在质子交换膜燃料电池中具有应用前景。     

质子交换膜燃料电池研究进展

质子交换膜燃料电池（proton exchange membrane fuel cell, PEMFC）因具有效率高、功率密度大、排放产物仅为水、低温启动性好等多方面优点,被公认为下一代车用动力的发展方向之一。然而,目前PEMFC在耐久性和成本方面距离商业化的要求还存在一定差距。为攻克上述两大难题,需要燃料电池全产业链的共同努力和进步。本文回顾了近年来质子交换膜燃料电池从催化剂、膜电极组件、电堆到燃料电池发动机全产业链的研究进展和成果,梳理出单原子催化剂、非贵金属催化剂、特殊形貌催化剂、有序化催化层、高温质子交换膜、膜电极层间界面优化、一体化双极板-扩散层、氢气系统循环等研究热点。文章指出,催化层低铂/非铂化、质子交换膜超薄化、膜电极组件梯度化/有序化、燃料电池运行高温化、自增湿化是未来的发展趋势,迫切需要进一步的创新与突破。     

Influence of casting conditions on the properties of sulfonated poly(ether ether ketone ketone)/phosphotungstic acid composite proton exchange membranes

The sulfonated poly(ether ether ketone ketone)/phosphotungstic acid (SPEEKK/PWA) composite membranes were researched for proton exchange membranes. The effect of casting condition on the properties of membranes was studied in detail. The study showed that the casting condition has great influence on the membrane properties because of the hydrogen bond between the SPEEK and PWA and the interaction between the SPEEKK and dimethylformamide (DMF). The PWA particles are well crystallized on the surface when the velocity of the solvent volatilization is very slow under the SEM. The study will favor further research on excellent composite membranes for proton exchange membrane fuel cells. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4020–4026, 2007     

Study of high-temperature proton exchange membrane through one-step encapsulation of ionic liquid in sulfonated poly(ether ether ketone)

The proton exchange membrane (PEM) is the core component of a high-performance proton exchange membrane fuel cell (PEMFC). Since the traditional PEM has the disadvantages of poor cell performance and high cost, a new kind of PEM with good proton conductivity, low cost and simple preparation should be explored. In this paper, several different binary hybrid membranes were successfully prepared through one-step encapsulation of different ionic liquids (ILs) in sulfonated poly(ether ether ketone) (SPEEK). The prepared membranes were characterized by scanning electron microscope (SEM), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), proton conductivity measurements and dynamic mechanical analysis (DMA). SEM images showed that ILs were fully doped into SPEEK. FT-IR and XPS proved that SPEEK and IL formed a new chemical bond combined with intermolecular hydrogen bonds. The TG results showed that the binary hybrid membranes could maintain stability even at 300°C. The water uptake and swelling ratio showed that the water absorption capacity of the binary composite membrane played a vital role in improving proton conductivity. The proton conductivity study showed that ILs doping also helped to improve the proton conductivity of the SPEEK membrane. When the doping amount of IL was maintained at 30 wt.%, it has the highest proton conductivity, 25 mS cm⁻¹ at 120°C. It was proved that anhydrous hybrid membrane tetraphenyl imidazole sulfate/SPEEK ([IM2][H₂PO₄]/SPEEK) could be used in PEMFC at medium temperature.     

富勒烯交联季铵化聚苯醚阴离子交换膜的制备

通过富勒烯C₆₀与乙二胺合成立体纳米分子C₆₀(EDA)₈,并以此为交联剂与三阳离子功能化聚苯醚制备了一系列交联型阴离子交换膜。C₆₀(EDA)₈中立体纳米结构有效地支撑了高分子链段,构建了更发达的离子通道,有效地提升了电导率。实验结果表明,随着C₆₀(EDA)₈加入量增加,交联膜的离子交换容量减小,而电导率却逐渐增加。当交联剂C₆₀(EDA)₈加入量为5%时,电导率提高了34%。此外,所制备的离子交换膜均表现出良好的抗溶胀能力、力学性能与耐碱性。     

高温质子交换膜研究进展

高温质子交换膜燃料电池解决了传统质子交换膜燃料电池催化剂易受CO等杂质气体毒化、水热管理复杂等问题,成为当今燃料电池发展的主要方向。高温质子交换膜是实现高温操作的关键部分。本文结合质子传递机理,分析了以水作为质子溶剂、非水质子溶剂质子交换膜以及无机固态质子导体膜的研究现状,认为有机/无机复合膜和非水质子溶剂膜,尤其是其中的磷酸掺杂的PBI膜是高温质子交换膜的发展方向。     

质子交换膜的应用与市场研究

介绍了质子交换膜的概念、产品及产品的类型、功能原理及主要性能指标;对质子交换膜的应用作了汇总与归纳;研究了质子交换膜在氯碱工业应用的市场规模与发展趋势、产品价格及其变化、主要产品供应商和国内主要消费企业;介绍了质子交换膜燃料电池及其应用状况前景、燃料电池质子交换膜市场现状与未来展望,分析了国内质子交换膜产业链状况.