Ion and water transport characteristics of Nafion membranes as electrolytes
Ion and water transport characteristics of Nafion membranes as electrolytes
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DOI：
10.1016/s0013-4686(98)00132-7
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发表时间：
1998-01-01
影响因子：
6.6
通讯作者：
Arimura, T
中科院分区：
文献类型：
--
作者：
Okada, T;Xie, G;Arimura, T
运输特性的Nafion膜，已出版较早，重新评估。据发现，膜的比电导率不仅是由离子的流动性，但在很大程度上也由离子与水和微观膜通道结构的相互作用。类似地，水传递系数，定义为通过膜的每法拉第传递的水的摩尔数，由两种效应控制：离子和水偶极子之间的静电效应，以及由于阳离子的大小而产生的效应。对电渗透水转移的贡献是水合为阳离子的水和流体动力学推动的水分子。离子的大小与通道直径相比，对电导率有重大影响，但也对水的输送有影响。结果表明，亲水性阳离子可以促进膜中的亲水域扩大，这是伴随着较低的膜电阻。在此基础上提出了设计高性能离子传导膜的准则。(C)1998爱思唯尔科技有限公司版权所有。
Transport characteristics of Nafion membranes, that have been published earlier, are re-evaluated. It is found that the specific conductivity of the membranes is not only determined by the mobility of the ions, but largely also by the interaction of ions with water and with microscopic membrane channel structures. Similarly, the water transference coefficient, defined as the number of moles of water transported per Faraday through the membrane, is governed by two effects: an electrostatic effect between ion and water dipoles, and an effect due to the size of the cation. Contributions to electro-osmotic water transfer are water of hydration to cations and hydrodynamically pushed water molecules. The size of the ion compared to the channel diameter, has a major impact on the electric conductivity, but also on water transport. It is shown that hydrophilic cations can promote an enlarged hydrophilic domain in the membrane, that is accompanied by a lower membrane resistance. Criteria for designing high performance ion conducting membranes are given based on this basis. (C) 1998 Elsevier Science Ltd. All rights reserved.