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

聚合物/炭黑复合材料具有作为PEFC隔膜的潜力。它要求对所产生的电流流动方向的低电阻率、弯曲强度和弯曲应变的强机械性能以及它们的耐热性能。[物理年]选择热弹性聚合物（TPE）作为粘合剂树脂。(1)本文研究了电阻率与所用炭黑形状的关系。选择了球形和片状CB。球形炭黑（SG）与热塑性弹性体（TPE）复合材料的电阻率较片状炭黑低，高温力学性能较片状炭黑高。(2)加载CB降低电阻率的机制是通过霍尔迁移率的变化而不是载流子密度的变化来解释的。[上一物理年度]为了获得更耐热的复合材料，今年采用了其他聚合物，如聚丙烯（pp）和聚苯硫醚（PPS）。有机-无机杂化材料 ...更多信息 e与聚二甲基硅氧烷（PDMS）和硅酸乙酯（ES）的混合物也用作粘合剂，并且它与SG以溶胶状态混合。(3)最低电阻率为几十mLI·cm，高于NEDO提出的电阻率小于10 mQ·cm的目标值。通过用PPS和SG制备复合材料，获得了弯曲强度大于50 MPa和弯曲应变大于1%的NEDO目标。(4)有机-无机杂化材料与SG复合制备的复合材料的电阻率比其他复合材料高10倍，机械强度比其他复合材料低1/10。这需要通过改变PDMS的分子量和改善凝胶条件来进一步研究。(5)在密闭容器水中进行140 ℃ × 600小时的耐久试验，PPS/SG复合材料的电阻率和力学性能无明显变化。(6)虽然TPE没有比PP和PPS更好的耐热性能，但用TPE和SG制成隔板。采用装有隔膜的单电池进行了电流-电压、交流阻抗和恒流运行测试。结果表明，为提高PEFC的性能，隔膜的电阻率应进一步降低。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