Application of Self-Humidifying Polymer Electrolyte Membranes for Fuel Cells

自增湿聚合物电解质膜在燃料电池中的应用

基本信息

批准号：
12555243
负责人：
WATANABE Masahiro
金额：
$ 4.16万
依托单位：
Yamanashi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Recently, we have proposed new self-humidifying polymer electrolyte membranes with highly dispersed nanometer-sized Pt and/or metal oxides for polymer electrolyte fuel cells (PEFCs) operated with dry H_2 and O_2. The Pt particles were expected to suppress the crossover by the catalytic recombination of H_2 and O_2, while the oxide particles (TiO_2) that have hygroscopic property were expected to adsorb the water produced at Pt particles together with that produced at the cathode reaction and to release the water once the PEM needs water. The PEFCs with these new PEMs demonstrated the superior performances and suppression of the crossover even under externally non-humidified condition, which are comparable to that of the conventional PEM fully humidified. In order to construct a practical PEFC stack, however, a mechanical strength of the PEM is an important property. Japan Gore-Tex developed a reinforced PEM with both a sufficient mechanical strength and high proton conductivity. It is desirable to prepare the self-humidifying PEM from a commercial reinforced PEM.In this research, we examined to develop a practical preparation protocol of such new PEMs and obtained the following results..1. The preparation protocol of TiO_2 nanoparticles in a commercial PEM via in-situ sol-gel reactions was developed, resulting in a transparent membrane with uniform distribution of TiO_2 among the membrane. A water adsorbability increased more than two times by dispersing only 2 wt % TiO_2 in the PEM.2. In order to get a uniform dispersion of Pt nanoparticles in the PEM, platinum-complex -cations were impregnated in the TiO2-PEM by an ion-exchanging reaction, followed by a reduction to Pt nanocrystals (0.1 mg/cm^2) with an aqueous solution containing excess neutral hydrazine. The Pt-dispersion process was optimized.3. The newly prepared Pt-TiO_2-PEM was confirmed to perform a self-humidifying operation in a PEFC with dry H_2 and O_2.

最近，我们提出了一种新型自增湿聚合物电解质膜，具有高度分散的纳米级 Pt 和/或金属氧化物，用于使用干 H_2 和 O_2 运行的聚合物电解质燃料电池（PEFC）。 Pt颗粒有望通过H_2和O_2的催化复合来抑制交叉，而具有吸湿性的氧化物颗粒（TiO_2）预计会吸附Pt颗粒处产生的水以及阴极反应中产生的水并释放出一旦 PEM 需要水，就需要水。即使在外部非加湿条件下，采用这些新型 PEM 的 PEFC 也表现出优异的性能和对交叉的抑制，这与完全加湿的传统 PEM 相当。然而，为了构造实用的PEFC堆叠，PEM的机械强度是一个重要的特性。日本Gore-Tex开发出一种增强质子交换膜，既具有足够的机械强度，又具有高质子传导率。期望从商业增强质子交换膜中制备自增湿质子交换膜。在这项研究中，我们研究了开发这种新型质子交换膜的实用制备方案，并获得了以下结果。.1．开发了通过原位溶胶-凝胶反应在商业质子交换膜中制备TiO_2纳米颗粒的方案，形成了TiO_2在膜中均匀分布的透明膜。通过在PEM.2中分散仅2wt%的TiO_2，吸水率增加两倍以上。为了使 Pt 纳米颗粒在 PEM 中均匀分散，通过离子交换反应将铂络合物阳离子浸渍在 TiO2-PEM 中，然后用含有过量中性肼的水溶液。优化了Pt分散工艺。 3．新制备的Pt-TiO_2-PEM被证实可以在干燥H_2和O_2的PEFC中进行自增湿操作。