Metal dioxide supported heteropolyacid/Nafion® composite membranes for elevated temperature/low relative humidity PEFC operation
Metal dioxide supported heteropolyacid/Nafion® composite membranes for elevated temperature/low relative humidity PEFC operation
复制标题
DOI：
10.1016/j.memsci.2005.12.044
复制
发表时间：
2006-08
影响因子：
9.5
通讯作者：
V. Ramani;H. Kunz;J. Fenton
中科院分区：
文献类型：
--
作者：
V. Ramani;H. Kunz;J. Fenton
含有不同无机杂多酸(HPA)添加剂的有机/无机复合膜可在高温(>；100°C)、低相对湿度(<；50%)操作下保持足够的质子电导率。然而，由于HPA添加剂在水介质中的溶解性，膜和膜电极组装(MEA)工艺严重受阻。本工作研究了负载HPA添加剂的金属氧化物骨架复合膜。事实证明，在商业载体上支持HPA不足以稳定添加剂。红外光谱表明，通过使用金属醇盐前驱体的原位溶胶-凝胶法，在一系列膜组成上实现了优异的稳定性。对于25μm厚的膜，膜是坚固的，表现出0.7 mA/cm2的低H_2交叉电流。在Nafion®上，复合膜的分解离子起始温度延长了30℃。使用稳定的复合膜制备的膜电极组件在运行的燃料电池中进行了高温和低相对湿度下的评估。在温度为12 0℃、相对湿度为35%的条件下，复合膜的电导率约为1.6×10−2S/cm。
Organic/inorganic composite membranes with different inorganic heteropolyacid (HPA) additives maintain sufficient proton conductivities for elevated temperature (>100°C) low relative humidity (<50%) operation. However, membrane and membrane electrode assembly (MEA) processing is severely curtailed because of the solubility of the HPA additives in aqueous media. Composite membranes with the HPA additive supported on metal dioxide frameworks were investigated in this work. Supporting the HPA on commercial supports proved to be inadequate to stabilize the additive. Superior stabilization, as demonstrated by IR spectroscopy, was achieved over a range of membrane compositions by using an in situ sol–gel approach using metal alkoxide precursors. The membranes were robust, and demonstrated low H2crossover currents of 0.7mA/cm2for a 25μm thick membrane. The decomposit ion onset temperature of the composite membrane was extended by 30°C over Nafion®. Membrane electrode assemblies prepared using the stabilized composite membranes were evaluated at high temperatures and low relative humidities in an operating fuel cell. The conductivities of the composite membranes at 120°C and 35% relative humidity were on the order of 1.6×10−2S/cm.