限制于全氟磺酸膜的固有属性，质子交换膜燃料电池（PEMFC）的操作温度通常在60-90℃范围内。本项目旨在构筑中高温质子传导纳米复合膜体系（120-140℃），以改善PEMFC电极反应动力学，削弱阳极CO中毒干扰，并且有效解决水、热管理等问题。核心思想是为离子和溶质在传输过程中提供额外的途径，以满足膜在高温和低湿度情况下的运行需求。将从复合膜的微结构和纳米尺度界面相互作用出发，采用多种模型计算方法，优选出与碳氢基或芳基离子聚合物相匹配的无机纳米添加材料。利用特制的微电极和电化学原子力显微技术，研究复合膜表面离子电导率、氧气渗透率、离子团簇分布、纳米孔道连通性等特殊属性，并且与膜化学微观结构信息建立“构效”关联。复合膜的稳定性是特别需要关注的问题，将重点考察反应中间产物（过氧化物及其自由基）对于聚合物骨架、聚合物自身链段配体、表面修饰材料及官能团的进攻位点和作用机理，并寻求有效解决方案。

This proposal is in the backdrop of current efforts to develop polymer electrolyte systems (PEM) for proton exchange membrane fuel cells (PEMFCs) which would enable operation at elevated temperatures in the range of 120 to 140℃ instead of the current state of the art perfluorinated systems which are designed for 60-90℃ operation. Such a transition has the potential of significantly improving not only the electrode kinetics especially for anodic CO tolerance and direct methanol oxidation but will also alleviate the thermal and water management issues. This project seeks to design nanocomposites that can provide additional variables in the transport phenomenon to largely mitigate the additional requirement for the aqueous based membranes to operate below 100% relative humidity with temperature elevation above the boiling point. The microstructure and nanoscale interactions that determine the durability and transport of ions & solute in polymer and polymer composites membranes will be thoroughly investigated by a home-built microelectrode system and electrochemical atomic force microscopy, along with molecular modeling studies and synchrotron based spectroscopic characterizations. Durability of the composite polymer will be a central concern in this project. However, this problem is expected to be tractable and resolvable from understanding of fundamental processes which determine the nature of formation of free radical at the electrode-electrolyte interface in terms of the polymer chemistry as well as choice of electrocatalyst and operating environment.