介孔磺酸化氧化锆的制备及复合膜研究

发布时间：2018-05-12 07:35

  本文选题：质子交换膜燃料电池 + 介孔材料　； 参考：《南京大学》2017年硕士论文

【摘要】：伴随着对清洁可再生能源的需求,燃料电池在交通、发电等领域得到广泛的研究和应用。作为质子交换膜燃料电池的关键部件,质子交换膜现阶段的性能和成本限制了质子交换膜燃料电池的商业化。全氟磺酸膜中添加微米级高比表面积的多孔材料是降低成本研究中的一个重要的方向。本文采用硫酸铵和氯氧化锆为前驱体制备了可调控比表面积的介孔磺酸化氧化锆(S-Zr02)。S-Zr02引入到Nafion溶液中后制备的混合膜的质子传导率得到了大大提高。该复合膜有望能作为低成本和高性能的质子交换膜应用在商业燃料电池中。氧化锆材料是一种常见的固体超酸,其磺酸基团具有传导质子的潜力。但传统的氧化锆的比表面积较小且表面官能化程度不高。本文提出新型的合成方法,采用硫酸铵和氯氧化锆为前驱体,以碳黑BP2000为模板,通过高温煅烧制备出S-Zr02。X射线衍射表征表明,当温度在600℃和650℃之间时,生成的S-Zr02是有利于质子传导的四方晶型。傅里叶红外光谱分析说明其中含有大量有利于质子传导的磺酸基团。扫描电子显微镜(SEM)、透射电子显微镜(TEM)表征发现,S-Zr02粉末是由平均粒径约为8 nm的纳米晶体聚集而成,纳米晶体之间的界限以及几个纳米尺度的通孔均表明介孔材料的成功制备。BET法表征的结果表明,制备的S-Zr02粉末的比表面积很高,最高的比表面积为181 m2 g-1,远高于大部分传统氧化锆材料。滴定法测定离子交换容量(IEC)测得其最高的IEC也高达0.48μequivm-2。同时,结合表征结果能够发现,样品的比表面积和IEC可以通过改变BP2000和前驱体的比例来调控,并且两者的比值是固定的。这说明S-Zr02比表面积的变化不影响其表面的化学性质,即磺酸基团的面密度是保持一致的。为了提高质子交换膜的性能,我们将介孔S-Zr02引入到Nafion基质中,制备出S-Zr02/Nafion复合膜。SEM表征发现,复合膜的平均厚度为20.5μm。TEM表征复合膜切片表明,高密度的离子团簇聚集在S-Zr02和Nafion之间界面,使得S-Zr02表面官能团化提高。磺酸离子簇聚集到S-Zr02的介孔的表面,能够有效地构建平均直径约为10nm的离子通道,确保通过整个膜的高效长程质子传输。实验分析发现,制备的S-ZrO2/Nafion复合膜的质子传导率最高达到0.83Scm-1,约为商业Nafion 211的7倍。在80℃、20～100%相对湿度的湿度范围内,S-ZrOa/Nafion复合膜的质子传导率均明显高于商业Nafion211膜,这得益于膜的高含水率。全电池测试结果表明,S-ZrOa/Nafion复合膜在0.6 V时最高电流密度和功率密度分别为1310 mAcm-2和786 mW cm-2,远高于商业Nafion211膜。复合膜的最高功率密度为988 mW cm-2,大大高于商业Nafion211膜。在低湿条件下,制备的S-ZrO2/Nafion复合膜功率密度也高于商业的Nafion211膜,这证明S-ZrO2/Nafion复合膜全电池性能优异,并能适应不同的湿度操作条件,大大优于目前商业的Nafion 膜。
[Abstract]:With the demand for clean and renewable energy, fuel cells have been widely studied and applied in transportation, power generation and other fields. As a key component of proton exchange membrane fuel cell, the performance and cost of proton exchange membrane at present limit the commercialization of proton exchange membrane fuel cell. The application of porous materials with high specific surface area in perfluorinated sulfonic acid membrane is an important research direction in cost reduction. In this paper, the proton conductivity of the mixed membranes with adjustable specific surface area of mesoporous zirconia (S-Zr02U. S-Zr02) was prepared by using ammonium sulfate and zirconium chloride as precursors. The proton conductivity of the mixed membranes was greatly improved after the introduction of S-Zr02U. S-Zr02 into Nafion solution. The composite membrane is expected to be used as a low-cost and high-performance proton exchange membrane in commercial fuel cells. Zirconia is a common solid superacid whose sulfonic group has the potential to conduct protons. However, the specific surface area of traditional zirconia is small and the degree of surface functionalization is not high. In this paper, a new synthesis method was proposed. The S-Zr02.X ray diffraction characterization was prepared with ammonium sulfate and zirconium chloride as precursors, carbon black BP2000 as template, and calcined at high temperature. The results showed that the temperature was between 600 鈩，

本文编号：1877715