耐久阴离子交换膜的高效阻醇设计及其甲醇燃料电池性能研究

The alkaline fuel cells based on the anion exchange membranes (AEMs) are expected to get rid of the use of the precious metal catalyst Pt, which exhibit important practical application prospect. Developing new AEMs with high ionic conductivity, good alkaline stability and resistance against methanol crossover is not only the key to realize practicable application and commercialization of the alkaline fuel cells, but also is the key scientific problem needed to be solved in this area. In this project, through the optimization design of the structure of AEMs, we will study the key factors influencing the alkaline stability of the skeleton structure and ionic group structure of AEMs and illustrate the internal relationship between the microstructure of the membrane and its property. Moreover, exploring a new method combined matrix enhancement with interface tuning to prepare AEMs with good resistance against methanol by using the intrinsic reaction of certain functional groups to fast constructing micro(nano) meter sized methanol barrier layers on the surface of the polymer. Further study the influence factors for controlling the thickness of the cross-linking skin layer and reveal the effect rule of the thickness, composition and aperture size of membrane on the ionic conduction, methanol resistance performance and methanol fuel cell performance. Additionally, optimizing the structure of membrane-electrode assembly (MEA) and screening appropriate binder to obtain new cognition of the three-phase compatibility among the membrane, the binder and catalyst layer, which can provide important experimental data to develop new AEMs for the practical application.

基于阴离子交换膜（AEMs）发展的碱性燃料电池，可摆脱贵金属催化剂Pt的使用，具有重要的实际应用前景。开发具有高效离子传导，良好碱稳定性兼具抗甲醇透过能力的AEMs材料，是实现碱性甲醇燃料电池实用化、商业化的关键，也是该领域急需解决的关键科学问题。本项目拟通过AEMs材料结构的优化设计，研究影响AEMs骨架结构和离子基团结构碱稳定性的关键因素，阐明膜的纳微结构与其性能的内在关系。探索利用特定功能基团的本征反应，在聚合物表面快速构建微 (纳)米级的交联阻醇层，建立主体增强与界面调控相结合的制备高效阻醇AEMs的新方法。深入研究交联层厚度的控制因素，并揭示交联层的厚度、组成及传输通道尺寸对离子传导、阻醇性能和甲醇燃料电池性能的影响规律。优化膜电极（MEA）的结构和筛选适宜的粘结剂，获得膜、粘结剂、催化层之间的三相界面相容性的新认知，为开发面向实际应用的新型AEMs材料提供重要的实验依据。

设计、制备拥有高OH-电导率和高碱稳定性的阴离子交换膜(AEMs)仍然面临着一些严峻的挑战。本项目系统研究了阳离子基团结构、聚合物主链结构与碱稳定性之间的关系；发现了阳离子结构中大的、自由的取代基团有助于阳离子碱稳定性的提高；拓展了利用酸催化的Friedel-Crafts聚合反应制备高性能聚合物的合成方法学；实现了主链非醚的阴离子交换膜材料，微孔型阴离子交换膜材料以及无规与嵌段共聚物膜材料的简便合成，并建立了通用制备技术平台。发展了主体增强与纳米填料界面调控相结合的高效阻醇策略，并通过调控同质粘结剂树脂的离子交换容量和粘结剂树脂在催化层中的聚集形态，改善了膜与催化层的界面兼容性并实现了燃料电池性能的显著提升。碱性稳定性测试结果表明，聚芳基咪唑鎓盐型阴离子交换膜poly-PhIM [OH]具有良好的耐碱性(在10 M NaOH中80℃处理100 天后，1H NMR谱未见明显降解), 碱性稳定优于大多数以报道的AEMs。这些研究结果为阴离子交换膜材料在燃料电池领域得到实际应用提供关键的数据支撑和坚实的实践基础。