Development of in-situ/ex-situ electrochemical measurement system for polymer electrolyte membrane fuel cells

通过原位电化学和非原位电化学技术的发展，构建了聚合物电解质膜燃料电池的电化学测量系统。迄今为止，pemfc的电池性能都是通过单个电池的I-V特性来评估的。本研究成功地建立了在细胞操作环境下正确测量细胞中使用的每种材料的基本方法。主要研究成果总结如下：首先，通过开发新型多孔微盘电极和多孔微环电极，对单独粉末催化剂和催化剂/PEM层状结构的电化学性能进行了估计。其次，通过采用一组微电极，可以实现PEM在厚度方向上的精确质子导电性。当测量的电导率与电流中断技术评估的电导率进行比较时，质子电导率的大小是一致的。第三，利用基于微定位特性的微圆盘电极，获得了一种新的质子交换膜酒精交叉评价方法。这使得PEM的定量交叉分析成为可能。其次，根据光谱电化学测量，研究了芳香醇作为新候选燃料的氧化还原机理。最后，通过改变水与甲醇的混合比例，采用交叉微阵列电极解决了聚合物电解质膜的离子电导率问题，这对于直接甲醇燃料电池（DMFC）的运行是有价值的。总之，通过设计原位/非原位电化学测量系统来评价PEMFC中功能材料，大大提高了材料和电池系统的电化学研究水平。

Electrochemical measurement system for polymer electrolyte membrane fuel cells(PEMFCs) has been constructed by developing in-situ and ex-situ electrochemical techniques. Thus far, cell performances of PEMFCs have been evaluated by I-V characteristics of the single cell. The present study has succeeded to establish fundamental methods to measure each material used in the cell properly under the cell-operation environments. Main research results are summarized as follows. First, by developing novel porous-microdisc electrode and porous-microring electrode, electrochemical properties of powder catalyst alone and catalyst/PEM layered structure have been estimated. Second, precise proton conductivity of PEM in thickness direction has become available by employing a set of microelectrodes. When the measured conductivity was compared with that assessed by the current interruption technique, the magnitudes of proton conductivities were well agreed. Third, a new method for alcohol crossover evaluation at a PEM has been attained, utilizing a microdisc electrode based on its micro-positioning feature. This enabled a quantitative crossover analysis at the PEM. Next, redox mechanism of an aromatic alcohol as a new fuel candidate has been investigated according to a spectroelectrochemistry measurement. Finally, ionic conductivity of polymer electrolyte membrane has been resolved employing an interdigitated microarray electrode by changing a water : methanol mixture ratio, which is worthwhile for operating the direct methanol fuel cell(DMFC). In conclusion, by designing in-situ/ex-situ electrochemical measurement system to evaluate the functional materials in the PEMFC, electrochemical study for the materials and the cell systems have been greatly improved.