【作者】 卢真；

【导师】 朱红；

【作者基本信息】 北京交通大学 ， 应用化学， 2010， 硕士

【摘要】 直接甲醇燃料电池(DMFC)具有安全可靠、携带方便、甲醇来源丰富等优点,是一种很有前景的清洁能源技术。质子交换膜是直接甲醇燃料电池的关键材料之一,但目前应用最广泛的Nafion膜由于保水性差、阻醇性能差、成本高昂等原因,限制了直接甲醇燃料电池的大规模商业化。针对这些缺点,本文以提高保水性、提高阻醇性能和降低成本为出发点,制备了三种质子交换膜,获得了以下一些成果：采用掺杂亲水无机物的方法改性Nafion膜,对SiO2分子筛进行了磺化,并制备了Nafion/磺化SiO2分子筛复合膜。XRD和SEM表明分子筛在膜内分布均匀。实验结果表明,复合膜的含液率要大于Nafion膜,并且有较好的抗溶胀能力。综合性能是磺化SiO2分子筛含量为5 wt%的复合膜最好,甲醇透过率比Nafion膜降低了一个数量级,而质子传导率都在0.01 S／cm以上,能满足燃料电池的应用要求。采用一步法合成了一种新的磺化聚酰亚胺(SPI),并制备成膜。结果表明,SPI膜具有比Nafion膜更高的含液率和溶胀度,但对温度和甲醇浓度不太敏感；质子传导率随着磺化度的提高而增大,只比Nafion膜略低；甲醇透过率随着磺化度的提高而增大,但仍低于Nafion膜。采用共混法制备了磺化聚酰亚胺／聚偏氟乙烯(SPI/PVDF)共混膜,SEM和XRD均表明PVDF在膜内分别比较均匀,但PVDF含量高时共混膜发生了相分离。与纯SPI膜相比,共混膜的含液率有所降低,但溶胀度也降低了。质子传导率随着PVDF含量的增大而减小但都大于10-3 S／cm。甲醇透过率随着PVDF含量的增大而降低,远低于Nafion膜,有较好的阻醇性能。本论文图64幅,表3个,参考文献76篇。更多还原

【Abstract】 Direct methanol fuel cell(DMFC) have many advantages, such as safe and reliable, easy to carry, rich source of methanol,et al. It is considered as a promising alternative energy source. Proton exchange membrane is one of the key materials in direct methanol fuel cell. Currently the membrane which is the most widely used is Nafion membrane. However, because of poor water retention, high methanol crossover, high costs and other factors, It has limited the large-scale commercialization of DMFC.In order to improve capacity of water retention and methanol resistant and reduce the cost, three novel proton exchange membranes are fabricated. The innovative achievements obtained are mainly as follows:Novel inorganic-organic composite membranes based on Nafion modified by doping hydrophilic inorganic. The SiO2 molecular sieve was sulfonated firstly. Then Nafion/sulfonated SiO2 molecular sieve was fabricated. It was shown by SEM and XRD that molecular sieve was distributed uniformly in the membrane. It was observed that the composite membrane had higher liquid content and better Anti-swelling capacity than Nafion membrane. The membrane with the best overall performance is Nafion/S-SiO2(5wt%) membrane. Compared with Nafion membrane, its methanol permeability had decreased by about one order of magnitude.At the same time, its proton conductivities are all above 0.01S/cm.This membrane can meet the requirements of fuel cell applications.A novel sulfonated polyimide was modified by one-step method. Then the SPI membranes were fabricated. It was observed that the liquid content and swelling degree of SPI membrane were higher than Nafion membrane. But they were not sensitive to temperature and methanol concentration. Proton conductivity of SPI membranes increased as the sulfonation degree increased, and is a little lower than Nafion’s. Methanol permeability of SPI membranes also increased as the temperature increased,but it was still lower than Nafion’s.SPI/PVDF blend membranes were fabricated by the methodology of polymer blend. It was shown by SEM and XRD that PVDF was distributed uniformly in the membrane. However, the phase separation existed in blend membranes when the content of PVDF is high. Compared with pristine SPI membrane, liquid content of blend membranes reduced and swelling degree also decreased. Proton conductivity of SPI/PVDF blend membranes reduced as the content of PVDF increased, but they were all above 10-3S/cm. Methanol permeability of SPI membranes also reduced as the content of PVDF increased, and were much lower than Nafion’s. Blend membranes had good methanol resistant performance.There are 64 figures,3 tables and 76 references in this thesis.更多还原