Development of proton conducting polyimide membranes and their polymer electrolyte fuel cell applications

研究了大豆分离蛋白膜的水稳定性与其化学结构的关系。由2，2 '-双-（4-磺基苯氧基）联苯胺（BSPOB）衍生的SPI在130℃的水中具有超过500 h的高水稳定性，在120℃和50%RH下具有0.05 S/cm的相当高的质子电导率，表明在100℃以上的聚合物电解质燃料电池应用中具有很高的潜力。采用简单的砜键交联方法，显著提高了膜的水稳定性，采用传统催化剂电极和SPI膜制备的膜电极具有与Nafion 112相当的PEFC性能。在90℃、80-90%RH、0.5 A/cm 2的恒定负载电流下运行1600 h，SPI膜的电池电压和电池电阻均未下降，表明SPI膜具有相当高的耐久性。采用传统催化剂电极和SPI膜的MEA即使在50%的高甲醇浓度下也显示出高的DMFC性能，结果表明，SPI膜比Nafion膜具有更低的甲醇和水的渗透率，因此SPI膜优于Nafion膜。使用这些SPI，制备催化剂电极。由催化剂电极和基于BAPBDS的SPI膜组成的MEA表现出较低的PEFC性能，但一些有待解决的问题变得清晰。

The relationship between water stability of SPI membranes and their chemical structures were investigated. SPIs derived from 2,2' bis-(4-sulfophenoxy)benzidine (BSPOB) displayed high water stability of more than 500 h in water at 130℃ and reasonably high proton conductivity of 0.05 S/cm at 120℃ and 50%RH, indicating high potential for polymer electrolyte fuel cell applications above 100℃. Simple crosslinking method using sulfone linkage was developed, which significantly improved the water stability of membranes.MEAs with conventional catalyst electrodes and SPI membranes displayed high PEFC performance comparable to that for Nafion 112. A PEFC with BSPOB-based SPI membrane was operated at 90℃, 80-90%RH and a constant load current of 0.5 A/cm2 for 1600 h without any decrease in cell voltage and any increase in cell resistance, indicating reasonably high durability of the SPI membrane.MEAs with conventional catalyst electrodes and SPI membranes displayed high DMFC performance even for high methanol concentration of 50%, indicating that SPI membranes were superior to Nafion membranes because of much lower crossover of methanol and water.Novel SPIs suitable for ionomer in catalyst layer were developed. Using these SPIs, catalyst electrodes were prepared. MEAs composed of the catalyst electrode and BAPBDS-based SPI membrane showed low PEFC performance, but some problems to be solved became clear.