金属有机框架材料中的质子传导及其在质子交换膜中的应用

质子交换膜（proton exchange membrane，PEM）是保证燃料电池安全、高效运行的关键部件。当前，Nafion及部分Nafion衍生物PEM被广泛应用于燃料电池、电解制氢、传感检测、液流电池等领域。但是，其仍存在制造成本过高、高效温度范围狭窄（\mathrm{约}\mathrm{20}~\mathrm{80}℃）等问题。近年来，部分金属有机框架材料（metal-organic frameworks，MOFs）因具有结晶性、可设计性和高比表面积等优点，作为潜在的新型质子导体，被用于修饰、改进现有高分子质子交换膜，或直接被作为主要质子传导介质制成质子交换膜，取得了一系列重要进展。本文详细介绍了在MOFs中五种质子传导的常见方式，综述了近年来国内外在高性能质子传导MOFs领域的代表性成果，总结了质子传导MOFs在质子交换膜中的三类常见应用方法，指出MOFs材料在提高PEM质子电导率、降低PEM成本、拓宽PEM高效工作区间等方面具有巨大的发展潜力。最后，本文提出现有MOFs在质子交换膜中的应用还存在稳定性、耐久性、有害物质逸出等方面的问题，这为新型MOFs质子交换膜的开发提供了参考与思路。     

Nafion/HZSM-5有相-无机复合质子交换膜的制备与性能研究

通过重铸的方法制备了Nafion/HZSM-5有机-无机复合质子交换膜,研究了添加HZSM-5纳米沸石分子筛颗粒对Nafion膜的结构、水吸收、质子传导率、热稳定性和化学稳定性的影响.与纯的重铸Nafion膜相比,含有5%(质量分数)HZSM-5分子筛的Nafion/HZSM-5复合膜具有更高的质子传导率,当HZSM-5的质量分数高于5%时,复合膜的质子电导率随着HZSM-5含量的增加有所降低,而Nafion/HZSM-5复合膜的水吸收率在HZSM-5质量分数为7.5%时最高,Nafion/HTSM-5复合膜的降解温度也高于纯的重铸的Nafion膜,Nafion/HZSM-5复合膜性能的提高可能与HZSM-5的酸性和特殊的孔道结构有关.     

硫酸化SnO2/SPPESK复合质子交换膜的制备及燃料电池性能

非氟聚合物磺化聚芳醚砜酮（SPPESK）具有甲醇渗透率低、化学、热稳定性高等优点,但其高的电导率需通过提高磺化度获得,导致膜因过度溶胀而失去尺寸稳定性。添加无机纳米颗粒可以有效提高膜性能,但因其表面缺少功能化基团,导致颗粒有机相容性差,阻醇性能和质子传导率不易同时提高。硫酸化改性的纳米颗粒因其表面具有酸性位点和硫酸基团,能够有效克服这一问题。本文制备表面硫酸化改性的SnO₂（SSnO₂）纳米颗粒并引入SPPESK基质制备有机无机复合质子交换膜。当SSnO₂含量不大于7.5%时,纳米颗粒具有良好的有机相容性,可均匀分散于聚合物基质。SSnO₂含量为7.5%时,80℃下复合膜吸水率（19.6%）比SPPESK原膜提高19%,接近Nafion115。颗粒诱导膜内离子簇的聚集扩大,降低了质子的传导阻力,质子传导率分别比SPPESK原膜和Nafion115膜提高48%和30%。同时,纳米颗粒增大了甲醇传递空间位阻,甲醇渗透率较SPPESK原膜和Nafion115膜分别降低46%和71%。直接甲醇燃料电池0.5V处功率密度分别比SPPESK原膜和Nafion115膜高205%和50%。     

用于质子交换膜的高质子传导率聚合物研究进展

质子传导率超过Nafion膜的质子交换膜是近年来研究的焦点。质子交换膜的质子传导率与它们的IEC值和形态有关。形成离子通道是开发高质子传导率的质子交换膜的一种有效方法。形成离子通道主要有3种:1)用嵌段共聚物的微相分离;2)侧链和支链磺化的聚合物;3)局部区域的高密集磺化。此外,与无机纳米材料形成纳米复合材料的质子交换膜也能提高质子交换膜的质子传导率及质子交换膜的机械强度、尺寸稳定性、耐氧化稳定性等性能。综述了关于用于高质子传导率的燃料电池质子交换膜(PEM)的聚合物的研究进展。对高质子传导率的燃料电池膜聚合物的发展趋势进行了展望。     

PAN多孔纳米纤维的制备及其吸附性能研究

以聚丙烯腈(PAN)为原料,以聚乙二醇(PEG)为造孔剂,通过静电纺丝制成PAN/PEG复合纳米纤维,再经水洗去除纤维中的PEG成分制备出PAN多孔纳米纤维。采用傅里叶变换红外光谱仪、扫描电子显微镜、比表面孔径测定仪、分光光度计分别对PAN多孔纳米纤维的结构、形貌、比表面积及吸附性能进行了表征。结果表明:PAN/PEG复合纳米纤维中两组分呈微观相分离状态,通过水洗可去除PEG组分制得PAN多孔纳米纤维;PAN多孔纳米纤维的直径随PEG含量及相对分子质量的增加而减小,而比表面积、孔体积以及吸附能力随PEG含量及相对分子质量的增加而增大。     

质子交换膜用铱基催化层的制备与成膜工艺研究

质子交换膜(Proton Exchange Membrane, PEM)电解池水电解技术是制氢技术的研究热点之一,具有电流密度高,可再生,无污染等优点。本文采用电解水的方法考察在使用不同型号Nafion膜的情况下,催化剂质量比与催化剂载量的关系。结果表明:低疏水性碳纸扩散层有利于提高水电解性能;催化剂载量越高,电解效果越好;以及使用Nafion115,IrO2与Nafion质量比为3∶1时,电解性能最好,稳定性最高。     

Sn掺杂CeO2中Ce3+的形成机制及其对质子交换膜燃料电池耐久性的影响

在质子交换膜燃料电池(PEMFC)运行过程中，产生的自由基会攻击质子交换膜，使其开裂或形成孔洞，导致电池失效。常见的改性方法是在质子交换膜(PEM)中添加自由基清除剂材料。基于此，本文合成了Sn掺杂CeO₂自由基清除剂，通过提高Ce³⁺浓度来增强其在PEMFC中自由基清除性能，避免PEM厚度迅速减薄，从而提高质子PEMFC的耐久性。密度泛函理论计算和试验结果表明，Sn掺杂会引起CeO₂产生晶格畸变，降低氧空位形成能，促进CeO₂中Ce³⁺的形成。同时，Sn²⁺的加入可将CeO₂-Sn样品中的Ce⁴⁺还原为Ce³⁺,提升Ce³⁺的浓度，从而提高PEM的耐久性。单电池测试结果表明，经70 h的开路电压衰减测试，CeO₂-Sn-5%改性后的质子交换膜组装的单电池电压衰减率最低(18%),且功率保留率(56%)比其他样品更高，表明该样品具有更优异的耐久性。     

聚丙烯腈/羧基化碳纳米管纳米纤维膜制备及对铅离子的吸附效果

为此制备了一种聚丙烯腈(PAN)/羧基化多壁碳纳米管(MWCNTs-COOH)复合纳米纤维膜并探究其对废水中Pb²⁺的吸附效果。将MWCNTs-COOH与PAN混合成溶液，通过静电纺丝技术，成功制备了PAN/MWCNTs-COOH复合纳米纤维膜；采用扫描电子显微镜观察其形貌；并在pH=3,5,7的条件下进行吸附实验，探究PAN/MWCNTsCOOH复合纳米纤维膜对Pb²⁺吸附性能及吸附机理，用准一级和准二级动力学模型模拟吸附动力学进一步阐述实验数据；通过过滤吸附实验进一步研究PAN/MWCNTs-COOH复合纳米纤维膜在实际应用中对水中Pb²⁺的清除性能。结果表明所制备的纳米纤维膜具有致密网状结构，形态良好；与pH=3,5条件下相比，在pH=7时，PAN/MWCNTsCOOH复合纳米纤维膜吸附性能最优，对Pb²⁺吸附率达到70%及以上，并在80 min左右达到平衡；吸附动力学研究表明PAN/MWCNTs-COOH复合纳米纤维膜对Pb²⁺可能是化学吸附；过滤实验显示PAN/MWC...     

质子传导膜内受限空间离子扩散过程

以具有纳米尺度孔径的聚偏氟乙烯(PVDF)质子传导膜为对象,研究电解质溶液中水合离子在受限空间内的传递行为,证明使用纳米尺度多孔膜代替离子交换膜用于液流电池过程的可行性。利用渗透实验分别研究浓度场、压力场,以及不同渗透压条件下膜中离子扩散和水迁移现象,分析传质行为与膜结构和组成之间的关系。结果表明离子在纳米尺度孔径的PVDF膜中的扩散过程与溶液中类似,表观离子扩散系数不受浓度差推动力的影响;离子交换膜中的表观离子扩散系数随浓度差推动力提高而增加。在渗透压作用下,自制PVDF纳米孔膜的水迁移速率低于Nafion 117膜,水迁移带来的负面影响更小;对于H⁺/VO²⁺的离子选择系数超过300,有效透过H⁺而阻止VO²⁺,适用于全钒液流电池过程。     

PAN/β-CD复合纳米纤维膜的制备及吸附性能研究

以聚丙烯腈(PAN)和β-环糊精(β-CD)为原料,以N,N-二甲基甲酰胺为溶剂,通过静电纺丝制备出不同β-CD含量的PAN/β-CD复合纳米纤维膜。采用扫描电镜、傅里叶变换红外光谱仪、X射线衍射仪、孔径及比表面积测定仪、紫外分光光度计对纳米纤维膜的形貌、结构、比表面积以及吸附性能进行了表征。结果表明:PAN/β-CD复合纳米纤维膜中,β-CD和PAN之间为简单的物理共混,β-CD保留了空腔结构;随着β-CD含量的增加,PAN/β-CD复合纳米纤维膜的直径增加,比表面积减小,对亚甲基蓝的吸附率增加;当β-CD相对PAN质量分数为40%时,PAN/β-CD复合纳米纤维膜的纤维直径粗细均匀,比表面积较小,为9.652 m2/g,对亚甲基蓝的吸附率较大,为97.48%。     

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.     

Solution‐blown SPEEK/POSS nanofiber–nafion hybrid composite membranes for direct methanol fuel cells

This study aims to develop novel hybrid composite membranes (NHMs) by impregnating Nafion solution into the porous sulfonated poly(ether ether ketone)/polyhedral oligomeric silsesquioxanes (SPEEK/POSS) nanofibers (NFs). The composite membrane was prepared by solution blowing of a mixture of SPEEK/POSS solution. The characteristics of the SPEEK/POSS NFs and the NHMs, including morphology, thermal stability, and performance of membrane as PEMs, were investigated. The performance of NHMs was compared with that of Nafion117 and SPEEK/Nafion composite membranes. Results showed that the introduction of POSS improved the proton conductivity, water swelling, and methanol permeability of membranes. A maximum proton conductivity of 0.163 S cm^?1 was obtained when the POSS content was 6 wt % at 80°C, which was higher than that of Nafion117 and SPEEK/Nafion. NHMs could be used as proton exchange membranes (PEMs) for fuel cell applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42843.     

Electrospinning preparation of a graphene oxide nanohybrid proton‐exchange membrane for fuel cells

Proton‐exchange membrane (PEM) is a core component of fuel cells that provides a channel for proton migration and transport. Prevailing PEMs fabricated using well‐established casting techniques have several limitations such as low proton conductivity, high fuel permeability, and poor stability. To overcome these shortcomings, this article introduces a graphene oxide (GO)‐based nanohybrid Nafion nanofiber membrane prepared using a facile electrospinning technique. On the one hand, electrospinning nanofibers provide efficient transport paths for protons, which tremendously enhance the proton conductivity. On the other hand, GO doping in PEM improves the self‐humidification, stabilities (mechanical, thermal, and chemical), and proton conductivity and reduces the fuel permeability. In this research, nanofiber membranes were obtained from Nafion solutions containing 0, 0.1, and 0.2 wt % GO via electrospinning. The morphology, structure, mechanical properties, proton conductivity, water uptake, and swelling properties of the membranes were studied. The results demonstrated that the comprehensive performance of PEM was significantly improved. The new findings may promote the wide application of PEM fuel cells. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46443.     

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。     

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

In this research, the preparation of low cost proton exchange membranes (PEMs) based on sulfonated poly ether ether ketone (SPEEK) for application in the microbial fuel cells (MFCs) is studied. Sulfonated polystyrene (SPS) and phosphotungstic acid (PWA) were employed to improve the performance of PEM through the creation of more proton pathways. At first, the sulfonation of PEEK and polystyrene were performed through two modified methods to obtain uniform and high degree of sulfonation (DS) of the polymers and then, the PEMs were prepared through the solution casting method. Accordingly, the formation of uniform skin layer was confirmed by the SEM micrographs. Blending the aforementioned additives to the SPEEK polymer solution significantly enhanced the proton conductivity, water uptake and durability of the modified membranes. The proton conductivities of SPEEK/SPS and SPEEK/PWA membranes at additive/SPEEK weight ratio of 0.15 were 45.3% and 26.2% higher than that of the commercial Nafion117 membrane, respectively. Moreover, the degradation times for the abovementioned modified membranes were 140 and 350 min which indicated satisfactory oxidation stability. Besides, the aforementioned membranes exhibited two times more water uptake compared to the neat SPEEK membrane. Finally, SPEEK/SPS and SPEEK/PWA membranes produced 68% and 36% higher maximum power in the MFC, compared to the commercial Nafion117 membrane. Therefore, the fabricated PEMs are potentially suitable alternatives to be used in the fuel cell applications.     

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。     

Solution blown sulfonated poly(ether sulfone)/poly(ether sulfone) nanofiber‐Nafion composite membranes for proton exchange membrane fuel cells

A composite membrane of sulfonated poly(ether sulfone) (SPES)/poly(ether sulfone) (PES) nanofiber (NF) mat impregnated with Nafion was prepared and evaluated for its potential use as a proton conductor for proton exchange membrane (PEM) fuel cells. The supporting composite nanofibrous mat was prepared by solution blowing of a mixture of SPES/PES solution. The characteristics of the SPES/PES NF and the composite membrane, such as morphology, thermal stability, and performance of membrane as PEMs, were investigated. The performance of composite membranes was compared with that of Nafion117. The introduction of solution blown NFs to composite membranes modestly improved proton conductivity, water swelling, and methanol permeability. Therefore, composite membrane containing SPES/PES NFs can be considered as a novel PEM for fuel cell applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42572.     

全钒液流电池用磺化聚芴醚酮质子交换膜的制备及性能

质子交换膜(PEM)作为全钒液流电池(VRFB)的核心组件之一,应当解决成本高昂、合成过程复杂等问题,并具备高质子传导率、低钒离子渗透率、高机械强度和优异化学稳定性等关键性能。本文基于四甲基双酚芴单体通过缩聚反应合成了一系列聚芴醚酮化合物PFEKs,再利用溴代反应将苯甲基功能化为溴甲基,接着通过4-羟基苯磺酸钠的SN₂亲核取代制得了一系列不同离子交换容量的磺化聚芴醚酮聚合物(SPFEKs)。通过溶液浇铸法成膜并酸化,得到一系列新型低成本PEMs。该合成路线的原料来源广泛,价格低廉,不涉及危险的磺化反应,易于工业放大。所得膜都具有良好的机械性能和氧化稳定性,其中SPFEK-40膜具有较高的质子传导率及离子选择性、较低的钒离子渗透率及面电阻,综合性能优异。以SPFEK-40膜组装的VRFB在电流密度为80 mA/cm₂^{时的能量效率}(EE)为88.2%,高于以Nafion 212膜组装的VRFB的84.8%。此外,以SPFEK-40膜组装的VRFB在30次循环后放电容量仅衰减至84.3%,远高于以Nafion 212膜组装的VRFB的66.1%。