【作者】 孟祥杰；

【导师】 韩克飞；

【作者基本信息】 北京化工大学 ， 有机化学， 2010， 硕士

【摘要】 质子交换膜燃料电池(PEMFC)是燃料电池领域中的研究热点,它采用固体聚合物作为电解质,可以大幅度提高电池的能量密度。质子交换膜是PEMFC的核心部分,该电解质膜的性质决定了电池的构造和运行的主要技术特征。目前广泛应用的全氟磺酸质子交换膜由于成本高,高温保水性能差以及甲醇透过系数高等原因限制了其产业化应用。本论文采用纳米表面工程技术对纳米TiO2表面进行化学修饰得到两种新的纳米颗粒修饰物,再将修饰物添加到Nafion(?)膜中制备了两种新型复合膜,并对膜的结构和性能方面进行了研究。具体研究内容如下：1、采用硅烷偶联剂法,成功合成了两种纳米TiO2表面化学修饰物TiO2@苯磺酸衍生物(D1)和TiO2@萘磺酸衍生物(C2)。其结构和粒径大小经过傅里叶红外光谱仪、透射电镜和激光粒度分析仪的表征确认。对于合成路线,我们采用分时段监测法进行了选择。2、采用流延成膜法向Nafion(?)膜中添加化合物D1和C2,首次制备了复合膜Nafion(?)/D1和Nafion(?)/C2。扫描电镜测试表明D1和C2在复合膜中均匀分布并且与Nafion(?)界面兼容性较好,没有明显的团聚现象。热重分析表明,D1和C2的加入没有减缓复合膜中磺酸基团的降解,复合膜的失重率变化趋势与吸水率相反。考察了膜的吸水率随温度和填料含量的变化趋势及其对质子电导率的影响,实验证实复合膜具有优异的高温保水性能,吸水率的升高改善了膜的导电性能。考察了复合膜的甲醇透过系数随温度和填料含量的变化趋势,利用隔膜扩散法测定甲醇透过系数,结果表明：D1和C2的加入显著改善了复合膜的阻醇性能,与Nafion(?)膜相比下降了约1个数量级。更多还原

【Abstract】 Proton exchange membranes are a key component in the development of proton exchange fuel cells(PEMFCs), which are devices for directly transforming chemical energy into electrical energy without producing waste products and environmental problems. Sulfonated perfluoro-polymers like Nafion(?), although having high proton conductivity, have the disadvantage of high cost and high methanol crossover. Consequently, there is a considerable amount of research on seeking alternatives for Nafion(?). Modifications on present PEM materials aimed at property enhancements is also an effective approach to obtain suitable PEMs for PEMFC.In this thesis, nano surface engineering technology has been applied to the surface modification of TiO2 and we have prepared two kinds of modificatory nano particles. Then they were added to the Nafion(?) membrane to prepare two new composite membranes, the structure and properties of which were studied later. Specifically, the content in this thesis is listed below:1. Two kinds of modificatory nano particles have been synthetized through silane coupling agent treatment, the structure and particle size of which were characterized by FT-IR, TEM and LPSA. The right synthetic routewe was selected and confirmed by the method of monitoring reaction in a period of time.2. C2 and D1 were added to the Nafion(?) membrane to prepare composite membranes Nafion(?)/D1 membrane and Nafion(?)/C2 membrane through the method of file casting firstly. D1 and C2 are uniformly distributed in composite membranes and good compatibility with Nafion(?) without obvious phenomenon of reunion as observed by SEM photographs. The TG experiment shows that addition of D1 and C2 to the Nafion(?) have not slowed the degradation of sulfonic acid in composite membranes. Study has focused on the trend of water content with different fillers content at different temperature and change of proton conductivity in impact of water uptake. It was observed that composite membranes have good high water-uptake. Study has also focused on methanol permeability with different fillers content at different temperature, which was measured by membrane diffusion method. The results showed that compared with Nafion(?) membrane, methanol permeability of composite membranes decreased by about one order of magnitude. The presence of D1 and C2 in the compsite membranes significantly decrease the methanol permeability.更多还原