Proton conducting and hydrophilic coordination polymers - synthesis, spectroscopic investigation and incorporation in fuel cell membranes

质子导电材料是燃料电池的关键组成部分，燃料电池利用氢和氧产生电能和热能。目前使用的最先进的材料是全氟磺酸离聚体Nafion，但它的使用仅限于高湿度值，因此，低温（< 80°C）。需要能够在更高温度下，最好是在无水条件下使用的新型功能材料。配位聚合物（CPs）是一类非常有前途的化合物，适合于这类应用。该项目的范围是在各种成分的燃料电池复合膜中创建、理解和开发质子导电配位聚合物（PCCPs），并实时监测湿度和质子电导率。特别强调的是引入- po3h2或- po3h -基团和额外的质子载体，以创造具有高而稳定的质子导电性的材料。为了更好地理解CPs的结构-性能关系以及水分子和粒径的作用，我们将详细研究不同相对湿度值下CPs的质子导电机理。为了研究它们在燃料电池中的可能应用，将制作和测试含有不同粒径PCCPs的复合聚合物膜。由于相对湿度对质子传导有很强的影响，因此将开发一种传感器来原位监测负载下细胞膜中的湿度。为了实现这一目标，我们汇集了Norbert Stock (Kiel), Michael Wark （Oldenburg）和Michael Tiemann （Paderborn）的研究小组，协同结合他们在配位聚合物合成/表征，复合膜中质子传导和传感方面的互补技能。pccp将在Stock组中合成。对于选定的体系，将建立控制粒径的PCCP纳米颗粒的合成策略。Tiemann小组将进行深入的温度依赖阻抗光谱研究，以研究质子传导途径，并将制造一个边缘电场（FEF）传感元件。该传感器元件将有助于在复合膜上进行现场阻抗测量，复合膜将由沃克小组准备和详细测试。各种含有磺酸盐和磷酸盐基团的聚合物以及酸碱聚合物混合物将被用于形成这种复合膜，此外，将研究由连续的pccp和聚合物层组成的膜。在与EWE研究所密切合作下一能源选择复合膜将用于制造膜电极组件。这些将应用于在实际燃料电池条件下运行的试验台。

Proton conducting materials are a key component in fuel cells, which use hydrogen and oxygen to produce electricity and heat. The state-of-the-art material currently employed is the perfluorosulfonic acid ionomer Nafion, but its use is limited to high humidity values and, hence, to low temperatures (< 80 °C). New functional materials that can be used at higher temperatures, preferably under anhydrous conditions, are needed. Coordination polymers (CPs) are one very promising class of compounds suitable for this kind of applications. The scope of this project is the creation, understanding, and exploitation of proton-conducting coordination polymers (PCCPs) in fuel cell composite membranes of various compositions and the real-time in-situ monitoring of humidity and proton conductivity. Special emphasis will be placed on introducing -PO3H2 or -PO3H- groups and additional proton carriers to create materials with a high and stable proton conductivity. To develop a better understanding for the structure-property relationship and the role of water molecules and particle size of the CPs, the proton conducting mechanism under various relative humidity values will be studied in detail. To investigate their possible application in fuel cells, composite polymer membranes which contain PCCPs of various particle sizes will be fabricated and tested. Since the relative humidity has a strong influence on the proton conduction a sensor will be developed to monitor in situ the humidity in the cell membrane under load. To accomplish this, we brought together the research groups of Norbert Stock (Kiel), Michael Wark (Oldenburg), and Michael Tiemann (Paderborn), synergistically combining their complementary skills in synthesis/characterization of coordination polymers, proton conduction in composite membranes, and sensing. The PCCPs will be synthesized in the Stock group. For selected systems synthetic strategies towards PCCP nanoparticles with controlled particle sizes will be established. The Tiemann group will carry out in-depth temperature-dependent impedance spectroscopic investigations to study the proton conduction pathway and will also fabricate a fringing electric field (FEF) sensing element. This sensor element will facilitate in-situ impedance measurements on the composite membranes which will be prepared and tested in detail by the Wark group. Various polymers containing sulfonate and phosphonate groups as well as acid-base polymer blends will be employed in the formation of such composite membranes and, in addition, membranes consisting of consecutive PCCPs and polymer layers will be studied. In close collaboration with the EWE Research Institute NEXT ENERGY selected composite membranes will be used to fabricate membrane-electrode assemblies. These will be applied in a test stand operating at realistic fuel cell conditions.