Preparation and Characterization of Highly Stable Ionomers and Ionomer Membranes for Medium Temperature Fuel Cells

在这个建议中，一个基本的方法，高度稳定的燃料电池膜和膜电极组件的目的。作为第一步，将合成磺化芳族单体和模型化合物，并使用不同的方法如热重（TGA）-FTIR偶联实验来研究它们的稳定性，所述磺化芳族单体和模型化合物另外用不同的吸电子基团和因此磺酸稳定基团进行改性（热稳定性，热分解产物的鉴定）;电子自旋共振（ESR）（自由基攻击稳定性）;循环伏安法（电化学稳定性）;在水、含水酸、含水碱、含水氧化剂中的储存（在这些溶剂中的稳定性，可从储存后离子交换容量的变化中读出）。在第二步中，具有最高稳定性的所选单体将通过合适的方法（亲核置换聚合和其它缩聚、Suzuki偶联等）聚合，并对其稳定性进行了研究。作为第三步，将制备新型聚合物的膜。这些膜还可以通过已知的方法另外交联以限制水吸收。此外，膜将任选地掺杂有无机化合物以改善其水储存能力、在高于100°C的T下的质子传导率和其热稳定性。还将通过项目合作伙伴实验室提供的方法对膜的热稳定性和（电）化学稳定性进行表征。作为第四步，从显示出最佳热稳定性和（电）化学稳定性的膜中制备膜电极组件，也使用各自项目合作伙伴制备的催化剂和电极，并将在PEFC和DMFC中进行表征和测试。该项目的一个重要方面是研究电极电解质界面以及聚合物离聚物在该界面处的功能和性质。这些研究的目标是能够更合理地改进电极，特别是具有来自ICVT的基于聚亚芳基的离聚物组分的电极。不同的新策略，以获得洞察的聚合物电解质燃料电池（PEFC）的催化活性层的过程中被开发。

In this proposal a fundamental approach for highly stable fuel cell membranes and membrane-electrode assemblies is intended. As a first step, sulfonated aromatic monomers and model compounds additionally modified with different electron-withdrawing and therefore sulfonic acid-stabilizing groups will be synthesized and investigated in terms of their stability using different methods like thermogravimetry (TGA)-FTIR-coupling experiment (thermal stability, identification of thermal decomposition products); electron spin resonance (ESR) (radical attack stability); cyclovoltammetry (electrochemical stability); storage in water, aqueous acid, aqueous base, aqueous oxidants (stability in these solvents, readable from the change in ion-exchange capacity after storage). In a second step, the selected monomers with the highest stabilities will be polymerised via suitable methods (nucleophilic displacement polymerisation and other polycondensations, Suzuki coupling, etc.), and also investigated in terms of their stability. As a third step, membranes of the novel polymers will be prepared. These membranes can also be additionally cross-linked via known methods to limit water-uptake. Moreover the membranes will optionally be doped with inorganic compounds to improve their water storage ability, proton conductivity at T more than 100°C, and their thermal stability. The membranes will also be characterized in terms of their thermal and (electro)chemical stability via the methods available in the labs of the project partners. As a fourth step, from the membranes showing the best thermal and (electro)chemical stabilities membrane-electrode assemblies will be prepared, also using catalysts and electrodes prepared by the respective project partners, and will be characterized and tested in both PEFC and DMFC. One important aspect of the project is the investigation of the electrodeelectrolyte interface and the function and properties of the polymeric ionomers at this interface. The goal of these investigations is to enable a more rational improvement of the electrode, in particular electrodes with poly-arylene-based ionomer components from the ICVT. Different new strategies to obtain insight into the processes of the catalytically active layer of the polymer electrolyte fuel cells (PEFCs) are to be developed.