质子交换膜微结构中质子输运复杂行为的模拟研究

质子交换膜中的质子输运行为是认识和发展质子交换膜燃料电池的核心问题。微结构调控是目前优化膜性能的最有效手段，然而对微结构与质子输运之间的联系仍然缺乏系统的理论陈述。本项目利用粗粒化的分子动力学方法，引入Gay-Berne椭球势考察磺酸基聚合物单元的各向异性，研究这种具有嵌段、梳状和两亲性结构的聚合物自组装形成的微晶相，并探索含微晶相结构的质子交换膜中质子的输运行为。在此基础上，研究不同因素如分子量、水含量、温度以及复合电极制作中的高温热压过程等对质子交换膜微结构和质子输运行为的影响；阐述与质子交换膜性能相关的经验和半经验公式在分子层面的具体体现。本项目的研究可以为理性设计微结构从而制备高性能质子交换膜提供理论基础和技术指导。

Proton transport in proton exchange membranes is a key issue to improve the performance of proton exchange membrane fuel cell. Tuning the microstructure is one of the most promising technologies to realize it. However, the relationship between microstructure and proton transport in proton exchange membranes remains unclear. The crystalline domain composed by sulfonated copolymer plays an important role in the microstructure and proton conduction, but none of computer simulation works has considered such phase domain originated from the anisotropic properties of the polymer units. We introduced Gay-Berne potential to describe such anisotropy in coarse grained molecular dynamics simulation. The influences of molecular weight, temperature, water uptake and the hot-pressing conditions for fabricating membrane electrode assembly on the microstructure and proton transport in the proton exchange membranes will be investigated. Such knowledge will facilitate more realistic understanding of the relationship between microstructure and proton transport behavior, and further provide guidelines for rational design proton exchange membranes with enhenced performance.