利用正电子湮没技术研究燃料电池用复合质子交换膜的微结构及其微结构-性能研究

Nowdays, proton exchange membrane fuel cells (PEMFCs) are considered as one kind of promising green power source for the application to military, industry and environment etc., due to their pronounced properties, such as stable operation, high electrochemical efficiency, fast start-up, low environmental pollution, and so on. Proton exchange membranes (PEMs), providing proton conduction between fuel and oxidant like hydrogen and oxygen, are one kind of the key components of PEMFCs. Tuning the microstructures and properties of advanced PEMs is one of popular research subjects concerning the PEMFCs. In this proposal, various advanced nano-materials with special microstructures, such as functionalized Carbon Nanotubes (CNTs), Metal Organic Frameworks (MOFs) and Covalent Organic Frameworks (COFs) etc., will be loaded in polymer membranes (for example, Nafion) to fabricate new nano-composite proton exchange membranes. Meanwhile, to tune the microstructures of composite PEMs, strong electric field and magnetic field, supercritical CO2 (SCCO2) will be applied during deposition of the membranes and post treatment of as-deposited membranes, respectively. It is aimed that the mechanical and thermal properties, gas barrier property and proton conductivity of the membranes can be improved by introducing advanced nano-materials and tuning microstructure. Sample chambers with variable temperature and humidity will be designed and constructed for the positron annihilation lifetime spectroscopy and electrochemical station measurements of the prepared PEMs, which will be simultaneously investigated with various conventional material analyzers. The proposed research is expected to precisely tune, from the bottom-up, the proton transport-paths, mechanical and thermal properties of the fabricated composite PEMs, to help us find the important roles that the additives and microstructures of composite PEMs played on their properties, and it will offer experimental and theoretical basis for research & development of advanced PEMs and the applications of new PEMFCs with high power density.

近年来燃料电池因其绿色、无污染、可持续应用等特点而备受军工、环境等领域的青睐。质子交换膜（PEMs）是决定燃料电池性能的重要材料，其微结构调控、性能研究是燃料电池研发方面的热门研究方向。本项目拟利用功能化改性的碳纳米管（CNT）、金属有机框架化合物（MOF）及共价有机框架化合物（COF）等具有特殊微结构的新型纳米材料掺杂高分子膜（如Nafion膜）制备复合PEMs，并利用电场、磁场、超临界CO2等方法诱导成膜，有效调控其微结构，达到提高其宏观力、热、气体阻隔及质子传导性能的目的。自制温度、湿度可控样品室，拟利用对高分子、多孔材料微结构灵敏的正电子湮没谱、电化学及其他常规材料分析方法研究质子交换膜的微结构影响其宏观性能的机制。本研究的开展有望从微观上有效调控PEM的质子传导路径、热力性能等，确立影响质子传导特性的微观关键因素，为优异性能PEM的研发和大功率燃料电池应用提供实验和理论依据。

近年来燃料电池因其绿色、无污染、可持续应用等特点而备受军工、环境等领域的青睐。质子交换膜（PEMs）是决定燃料电池性能的重要材料，其微结构调控、性能研究是燃料电池研发方面的热门研究方向。本项目拟利用功能化改性的碳纳米管（CNT）、金属有机框架化合物（MOF）等具有特殊微结构的新型纳米材料掺杂高分子膜（如Nafion膜）制备复合PEMs，并利用了外强磁场、多种方法成膜，有效调控了复合膜微结构，提高了其宏观力、热稳定性，特别是极高提高了其质子传导性能。自制了温度、湿度可控样品室，利用高分子、多孔材料微结构灵敏的正电子湮没谱、电化学及其他常规材料分析方法研究了质子交换膜的微结构影响其宏观性能的机制。本研究的开展从微观上有效调控了PEM的质子传导路径、热力性能等，阐明了高联通的质子水通道是决定质子交换膜质子传导特性的微观关键，复合膜的质子导电率可达0.25 S/cm，单电池功率密度达到1.2 W/cm^2。 本项目研究为优异性能PEM的研发和大功率燃料电池应用提供实验和理论依据。