用于自增湿质子交换膜燃料电池的限域沸石-全氟磺酸“结构”复合膜的相关研究

High-temperature self-humidifying proton exchange membrane fuel cell (PEMFC) is currently one of research hot topics in PEMFC field because it simplifies system design and structure, increases energy utilization efficiency, enhances system reliability and optimizes water and heat management processes. In order to solve the problems of phase separation and decreased proton conductivity that appear generally during the preparation of high-temperature tolerant self-humidifying composite membrane, this project proposes a novel confined zeolite-PFSA "structure" composite membrane. The new structure design utilizes water adsorption capacity of zeolite, and decreases the formation possibility of discontinuous zeolite phase which can hinder proton transport due to the aggregation of zeolite particles. Moreover, thermal stability and proton conductivity of "structure" composite membrane are expected to be improved remarkably by the interaction between zeolite and PFSA within confined space. This project will investigate the effects of preparation parameters on physicochemical properties and electrochemical performances of "structure" composite membrane and cell performances of membrane-electrode assembly to disclose the interaction within confined space and the structure-property-performance relationship. Also this project will investigate mass transfer and reaction processes within "structure" composite membrane and membrane-electrode assembly to understand high temperature tolerance behavior and self-humidifying mechanism via in situ, real-time and dynamic characterization methods, thus creating new idea, developing new route and inventing new method for the development of high temperature tolerant self-humidifying membrane with high performance.

耐高温自增湿质子交换膜之应用于燃料电池，简化了系统设计和结构、提高了能量利用效率、增强了系统可靠性和优化了水管理和热管理过程，已经成为当前质子交换膜燃料电池领域的研究热点。针对当前耐高温自增湿复合膜制备过程中普遍存在的相分离产生和质子导电性降低的问题，本项目拟开展限域沸石-全氟磺酸"结构"复合膜的研究，该复合膜的结构设计既发挥了沸石的保湿作用，又减少了阻碍质子传递的不连续相出现的可能性，通过在限域空间内沸石与全氟磺酸的相互作用，有可能大幅度提高复合膜在高温和无加湿情况下的热稳定性和质子导电能力。本项目将研究制备因素对"结构"复合膜的物理化学性质、电化学性能以及膜电极组件的电池性能的影响，揭示限域空间内相互作用的规律和材料的构效关系，利用原位实时动态表征方法研究膜及膜电极组件的传质和反应过程，了解其耐高温和自增湿机制，为耐高温高性能自增湿膜的研究开创新思路、构建新途径、创造新方法。

目前，全氟磺酸膜是质子交换膜燃料电池中最常用的电解质膜，在完全湿化的情况下，全氟磺酸膜具有优异的质子导电性能和长期操作稳定性。然而，全氟磺酸膜较低的热稳定性和其质子导电性随着膜湿化程度的降低而显著降低的特点导致了电池系统复杂的热管理和水管理问题，增加了系统设计和操作的复杂性、降低了能量转化效率和可靠性以及增加了系统的尺寸和成本。本项目研发了一系列具有自主知识产权的新型限域沸石-全氟磺酸“结构”复合膜，通过系统研究膜基底和沸石层的种类和几何参数，确定了影响“结构”复合膜性能重要因素；在此基础上构建的负载贵金属的沸石-全氟磺酸“结构”复合膜能够在没有加湿的条件稳定操作在160oC；构建的金属有机骨架-全氟磺酸“结构”复合膜为进一步提高电池在高温和低湿度下的性能提供了可能；利用本项目研发的原位实时表征装置，加深了对水吸附/脱附过程和电化学过程的理解，阐明了“结构”复合膜的自增湿机制。这些创新性的研究成果和科学认知，为开发耐高温高性能自增湿质子交换膜奠定了重要的实验依据和科学基础。