纤维增强PAEK/QPAEK高温质子交换膜的构筑和性能研究

Considering the issues about the poor mechanical properties and the short cycle durability under startup-shutdown condition of high temperature proton exchange membranes,this project will construct one kind of fiber reinforced high temperature proton exchange membrane. First, to overcome the compatibility problem between alkaline polymer (QPAEK) with fiber reinforcement (PAEK), nanofiber mats consisted of PAEK and precursor of QPAEK will be produced by a dual electro-spinning method, and then, the phosphoric acid doped fiber reinforced PAEK/QPAEK high temperature proton exchange membranes will be prepared by dealing the nanofiber mats with some kind of special solvent, trimethylamine and phosphoric acid, respectively. On this basis, we will carry out the research on exploring the influence of fiber volume fraction, structure and phosphoric acid doping level on the mechanical properties, clarifying the effect of fuel cell operating conditions on mechanism of membrane mechanical fatigue, establishing a mathematic model to depict the mechanical fatigue process, investigating a suitable accelerated ageing test, and based on this project, providing a powerful technical support on optimizing the high temperature proton exchange membranes and evaluating the durability, promoting the practical application of high temperature proton exchange membrane fuel cells.

针对高温质子交换膜机械性能差，在高温燃料电池启、停循环条件下寿命短这一问题，本项目拟构筑一种纤维增强高温质子交换膜。首先，利用高压静电纺丝技术将增强纤维和碱性聚合物前驱体交织电纺制备纤维毡，解决碱性聚合物（QPAEK）与增强纤维（PAEK）兼容性差这一技术瓶颈；然后，通过溶剂处理、季铵化、磷酸浸渍等处理过程构筑磷酸掺杂纤维增强PAEK/QPAEK高温质子交换膜。在此基础上，研究纤维结构、纤维体积分数、磷酸掺杂含量对机械性能的影响机制，探索电池操作环境使膜材料产生机械疲劳的作用机制，建立相关数学模型，考察加速老化测试技术，为优化高温质子交换膜和评价高温质子交换膜寿命提供技术支撑，推动高温燃料电池技术的发展。

针对高温质子交换膜机械性能差，在高温燃料电池启、停循环条件下寿命短这一问题，本项目基于结合双电纺丝工艺和溶剂蒸汽退火技术开发了一种具有聚合物增强纤维的高温质子交换膜制备技术。本项目成功制备了一种聚醚砜纤维嵌入季铵盐聚芳醚酮基质的纤维增强膜，其中对磷酸呈惰性的聚醚砜纤维在增强膜中对机械稳定性方面发挥重要作用。凭借聚醚砜纤维的优异机械性能和季铵盐聚芳醚酮与磷酸的强结合能，本发明的酸掺杂增强型季铵盐聚芳醚酮膜比传统改性膜具有更优异的综合性能，例如更高的酸掺杂水平，更高的机械强度和更优异的尺寸稳定性。此外，这种独特结构对尺寸稳定性的影响在高温下甚至更加明显。基于该高温质子交换膜的膜电极在不加湿的氢气和空气燃料供给下，在160 oC的高温下成功运行，并获得430 mW cm-2的最大功率密度。