碱性膜燃料电池的高效长寿命阴离子交换膜研制及构效关系研究

Based on the high cost of proton exchange membrane fuel cells (PEMFCs), anion exchange membrane fuel cells (AEMFCs) have been developed as a desirable alternative to PEMFCs because of their advantage in utilizing nonprecious metal materials as the electrocatalysts. Alternatively, this project aims to solve some limitations in anion exchange membrane, such as: insufficient ionic conductivity, inferior chemical stability of cationic group and polymer backbone of AEM. Understanding the fundamental science and developing the basic technologies associated to the key materials would be our primary research. Firstly, we combine theoretical calculations and experiments in order to understand the degradation mechanisms of different quaternary ammonium cationic group in alkaline condition. With the guide of mechanism study, we will be able to design and synthesize the most stable alkaline groups with high conductivity. Secondly, the appropriate grafting of cationic group on polymer backbone will be studied as well as the role of main chain polymer in the degradation process. The key structural factors between polymer backbone and cationic group related to the performance will then be revealed. Thirdly, for improving the oxidation resistance of AEM, in situ growth method is employed to grow nanoparticles on the surface of AEM, and fabricate the “layer-structure” alkaline composite membrane. The membrane electrode assembly will be fabricated based on home-made membranes and the performance of single cells will be evaluated. This project will lay scientific foundation for the further development of AEMFCs by providing the experimental basis and theoretical guidance for AEMFCs, and ultimately promote the commercialization of low-cost fuel cell technologies.

基于目前质子交换膜燃料电池高成本问题，碱性阴离子交换膜燃料电池因其可以使用非贵金属催化剂，被视为未来最具有潜力替代质子交换膜燃料电池的一种新型电池。本项目围绕碱性膜燃料电池阴离子交换膜中：离子传导率较低，阳离子与聚合物骨架化学稳定性较差等关键科学问题和技术瓶颈展开系统研究。拟结合量化计算和实验手段，系统研究季铵阳离子基团的降解机制与规律，优选并合成高效、稳定的碱性阳离子。优化阳离子与聚合物骨架的接枝方式，调控碱性膜内微观相分离程度，探索聚合物骨架与阳离子基团的匹配性机制，揭示其构效关系。以提高碱性膜抗氧化性为目标，利用原位生长等方法, 在碱性膜的表面生长致密的无机材料，制备高效、长寿命“层状”结构碱性复合膜；组建基于自制碱性膜的单电池，并对其进行性能评价。本项目的研究将为碱性膜燃料电池的深入发展奠定科学基础，提供实验依据和理论指导，推动超低成本燃料电池的发展。

随着新能源产业的发展，燃料电池以其高效、环保、可持续等优点在新能源领域中脱颖而出。燃料电池中聚电解质膜燃料电池已在航天、汽车、移动式电源等方面得到了广泛的发展。基于目前质子交换膜燃料电池高成本问题，碱性阴离子交换膜燃料电池因其可以使用非贵金属催化剂，被视为未来最有潜力替代质子交换膜燃料电池的一种新型聚电解质膜燃料电池。本项目围绕碱性膜燃料电池中阴离子交换膜离子传导率低、阳离子与聚合物骨架化学稳定性差、尺寸稳定性不足等关键科学问题和技术瓶颈展开系统研究。结合MD模拟、DFT理论计算及实验手段，系统研究了阳离子基团降解机制与规律，设计合成碱性条件下具有高降解能垒的季铵阳离子基团P-ASU，通过Menshutkin反应将其远程接枝于非氟骨架成功研发了超强耐碱ASU负载型功能聚合物膜材料；基于“微相分离”理论优化阳离子与聚合物骨架的接枝方式，调控碱性膜相分离程度，探索骨架与阳离子匹配机制并揭示构效关系，合成出多阳离子交联型SEBS基嵌段聚合物碱性膜、多阳离子交联聚联苯哌啶阴离子交换膜等膜材料，大幅度提升AEM的耐碱性与离子传导率；开发具有普适性的“无机材料表面阳离子改性技术”，赋予了无机材料离子交换功能，促进了无机材料在AEM中应用，结合原位生长、静电喷涂等方法制备了“层状”和“三明治”等结构的有机-无机复合膜，不仅有效提升了复合膜的离子传导率，机械性能以及尺寸稳定性，而且膜内的无机层还能作为保护层，有效提高复合膜的化学寿命，复合膜策略具备很好的普适性，可被高效应用在其他AEM的设计中。考虑到碱性膜在燃料电池中的放电能力，组建基于自制碱性膜的单电池，并对其进行工艺优化与性能评价。本项目研究为碱性膜燃料电池的深入发展奠定科学基础，提供实验依据和理论指导，推动超低成本燃料电池的发展。