高性能-抗溶胀聚丙烯基多级相分离结构阴离子交换膜

In order to balance the contradiction between mechanical stability and electrochemical performance of anion exchange membranes (AEMs) in fuel cell systems, in this proposal we propose the synthesis of a polypros polypropylene-based anion exchange membrane with multi-level hydrophilic/hydrophobic phase separation structures for exploring their application potential as AEMs. By virtue of the excellent adsorptivity of polypropylene (PP), a multi-level hydrophilic/hydrophobic phase separation structure can be constructed in mesopores of polypros PP membranes through several polymerization methods such as “radical polymerization method”, “atom-transfer radical polymerization method”, or “layered radical polymerization method”. The as-constructed multi-level phase separation structure can perform as a “highway" for hydroxide ions transportation, rendering the obtained AEM with a lower ion exchange capacity but a higher ionic conductivity. Meanwhile, the low-cost but robust polypros PP skeleton can provide a sufficient rigid support and hydrophobic isolationin working operating condition, making these AEMs possess a board commercial application prospect in fuel cell systems. Furthermore, based on the experimental results, density functional theory and coarse-grained molecular dynamics will be applied to reveal the theoretical mechanism of this phase separation structure in molecular level and polymer unit cell level. The analytical model of ion transportation “highway” will be also explored, which may provide some theoretical supports in AEM research field.

为解决燃料电池用阴离子交换膜（AEM）机械性能与电化学性能之间的矛盾，本申请提出制备“高性能-抗溶胀聚丙烯基多级相分离结构阴离子交换膜”。利用聚丙烯多孔膜的吸附性能，采用自由基聚合、原子转移自由基聚合与分层自由基聚合等方法在聚丙烯孔内构建亲-疏水相分离结构。通过在孔内以不同离子交换前驱体与疏水前驱体合成构建氢氧根离子传递的“高速通道”，该类AEM有望实现“低离子交换容量-高离子传导率”这一目标。聚丙烯骨架可提供足够的刚性支撑与疏水隔离，成本低廉，因此制备的AEM有望成为一类有商业化应用价值的阴离子交换膜材料。在此基础上，本申请拟采用密度泛函与粗粒化分子动力学方法从分子尺度和聚合物晶胞尺度探讨“亲-疏水”相分离结构的理论化学基础，探索获得氢氧根离子传递“高速通道”的理论模型，从而对阴离子交换膜结构设计与合成提供一定的理论支撑。

针对碱性燃料电池用阴离子交换膜存在的离子传导率低、耐碱性差等问题，以及锂硫电池体系隔膜的无选择透过性、无法阻拦溶解的多硫化物等问题，本研究围绕聚丙烯基离子交换膜开展了系统的研究工作；利用聚醚砜类的模型高分子，从分子结构设计角度建立了提高阴离子交换膜耐碱性的一般性策略；围绕燃料电池的三相界面，建立了燃料电池的三相界面与高分子结构的优化策略，实现了高效的燃料电池性能。上述系列研究，取得了一系列科学结果，其中包括：1.实现了聚丙烯基膜的表面活化，并在其表面实现了分层聚合，通过功能化反应可以构建各类具有不同基团的阴离子交换膜；2.建立了提高阴离子交换膜耐碱性的通用性策略，提出“捕鼠夹效应”，该效应结合取代基的占位效应显著提升了离子交换膜的耐碱性；3.利用聚丙烯基隔膜，结合软硬酸碱理论实现了对多硫化物穿梭效应的有效抑制；4.建立了基于相分离结构的燃料电池三相界面设计策略，并成功将之应用于氢氧燃料电池和金属-空气燃料电池体系。.项目目前发表SCI论文两项，影响因子均大于10；目前在投SCI论文4篇，发表之后将继续补充至项目成果；毕业研究生1人，在读博士生1人，在读研究生4人。