Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305 (USA).
ChemSusChem. 2015 Apr 24;8(8):1472-83. doi: 10.1002/cssc.201500133. Epub 2015 Mar 27.
There is a delicate balance between ion exchange capacity (IEC), conductivity, and dimensional stability in anion exchange membranes as higher charge content can lead to increased water uptake, causing excessive swelling and charge dilution. Using highly-charged benzyltrimethylammonium polysulfone (IEC=2.99 mEq g(-1) ) as a benchmark (which ruptured in water even at room temperature), we report the ability to dramatically decrease water uptake using a semi-interpenetrating network wherein we reinforced the linear polyelectrolyte with a crosslinked poly(styrene-co-divinylbenzene) network. These membranes show enhanced dimensional stability as a result of lower water uptake (75 % vs. 301 % at 25 °C) while maintaining excellent hydroxide conductivity (up to 50 mS cm(-1) at 25 °C). These improvements produced an enhanced alkaline fuel cell capable of generating 236 mW cm(-2) peak power density at 80 °C. This method is easily adaptable and can be a viable strategy for stabilizing existing systems.
在阴离子交换膜中，离子交换容量（IEC）、电导率和尺寸稳定性之间存在微妙的平衡，因为较高的电荷含量会导致水吸收增加，从而导致过度溶胀和电荷稀释。以高电荷的苄基三甲基铵聚砜（IEC=2.99 mEq g(-1)）为基准（即使在室温下也会在水中破裂），我们报告了使用半互穿网络来显著降低水吸收的能力，其中我们使用交联的聚苯乙烯-共-二乙烯基苯网络增强了线性聚电解质。这些膜由于吸水率较低（在 25°C 时为 75% 对 301%）而具有更好的尺寸稳定性，同时保持了优异的氢氧化物电导率（在 25°C 时高达 50 mS cm(-1)）。这些改进提高了碱性燃料电池的性能，使其在 80°C 时能够产生 236 mW cm(-2)的峰值功率密度。这种方法易于适应，是稳定现有系统的可行策略。
