Mechanism of Lowering the Resistivity of Composites used for PEFC and Endurance Test of Them

聚合物与炭黑复合材料在PEFC中具有作为分离器的潜力。它要求对产生电流的流动方向具有低电阻率，具有较强的弯曲强度和弯曲应变的力学性能及其耐热性。[第一个物理年]选择热弹性聚合物（TPE）作为粘结树脂。(1)研究了电阻率与炭黑形状的关系。选择了球形和片状CB。与片状炭黑相比，球形炭黑与TPE复合材料在高温下具有更低的电阻率和更强的力学性能。(2)载CB降低电阻率的机理是霍尔迁移率的变化，而不是载流子密度的变化。【上一个物理年】为了获得更多的耐热复合材料，其他聚合物如聚丙烯（pp）和聚苯硫醚（PPS）在今年被采用。以聚二甲基硅氧烷（PDMS）和硅酸乙酯（ES）为粘结剂，与SG以溶胶态混合。(3)最低电阻率为几十mLI-cra，高于NEDO设定的目标电阻率小于10 mli -cm。用PPS和SG制备复合材料，获得了抗弯强度大于50mpa，弯曲应变大于1%的NEDO目标。(4)与其他复合材料相比，有机无机杂化材料与SG复合材料的电阻率提高了10倍，机械强度降低了1 / 10。这需要通过改变PDMS的分子量和改善凝胶条件进行进一步的研究。(5)在密封良好的容器水中140oCX600hrs的耐久试验中，PPS和SG制备的复合材料的电阻率和力学性能没有变化。(6)虽然TPE的耐热性能不如PP和PPS，但用TPE和SG制备了隔膜。在一个装有该分离器的单体电池上进行了电流-电压、交流阻抗和恒流运行试验。研究表明，为了提高PEFC的性能，应进一步降低分离器的电阻率。少

Composites made with polymer and carbon black have a potential to separator used in PEFC. It requires a low resistivity to the direction of generated current flow, strong mechanical properties of bending strength and bending strain and their heat-resistive property.[First Physical Year] A thermo-elastic polymer (TPE) was selected as a binder resin.(1) Dependence of resistivity on the shape of used carbon blacks (CB's) has been studied. Spherical and flake shaped CB's have been chosen. The composite made with spherical CB (SG) and TPE showed lower resistivity and stronger mechanical properties in high temperatures than that made with flake CB.(2) The mechanism of lowering resistivity with loading CB is explained by the change in Hall mobility rather than the change in carrier density.[ Last Physical Year ] In order to get more heat resistive composites, other polymers such as pllypropylene (pp) and polyphenylene sulfide (PPS) have been employed in this year. Organic-inorganic hybrid mad … More e with polydimethylsiloxane (PDMS) and ethyl silicate (ES) is also used as a binder and it is mixed with SG in a sol state.(3) The lowest resistivity is several tens mLI-cra which is higher than the goal resistivity less than 10 mQ-cm which was set by NEDO. The NEDO goals for bending strength of above 50 MPa and bending strain of above 1 % are obtained by making the composite with PPS and SG.(4) The composites made with organic-inorganic hybrid and SG have shown higher resistivity by ten times and lower mechanical strength by one-tenth than other composites. That requires further studies by changing the molecular weight of PDMS and by improving gel conditions.(5) The composites made with PPS and SG showed no change of resistivity and mechanical property under the endurance test of 140oCX600hrs in a well-closed container water.(6) Although TPE did not have a better heat resistive property than PP and PPS, a separator was made with TPE and SG. A single cell equipped with the separator was employed for the tests of current-voltage, ac impedance and constant current running. It has been shown that the resistivity of the separator should be more reduced for higher performance of PEFC. Less