Elastic Long-Chain Multication Cross-Linked Anion Exchange Membranes
Elastic Long-Chain Multication Cross-Linked Anion Exchange Membranes
复制标题
弹性长链多阳离子交联阴离子交换膜
DOI：
10.1021/acs.macromol.6b01140
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发表时间：
2017-04-25
期刊：
影响因子：
5.5
通讯作者：
Zhuang, Lin
中科院分区：
文献类型：
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作者：
Han, Juanjuan;Zhu, Liang;Zhuang, Lin
阴离子交换膜（AEM）是一类有前途的材料，使非贵金属用作燃料电池中的催化剂。与它们的酸性对应物（通常为Nafion和其他基于全氟磺酸盐的膜）相比，AEM中的低OH电导率仍然是一个问题，因为这些材料是针对实际应用开发的。交联的大分子结构是优化具有高离子交换容量（IEC）的AEM的离子电导率和水溶胀之间的折衷的流行方式。然而，常见的交联AEM（例如，X（QH）QPPO）的交联度高，交联点之间的分子量低，通常机械上是脆性的。此外，AEM中的交联会阻碍OH-的传输，导致不令人满意的电导率。在这里，我们报告了一系列弹性和高导电性的聚（2，6-二甲基苯醚）（PPO）为基础的AEM（x（QH）（3）QPPO）含有灵活的，长链，多阳离子交联。与先前报道的常规x（QH）QPPO膜和多阳离子未交联材料相比，x（QH）（3）QPPO样品的强度和柔韧性显著改善。这些新材料（x（QH）（3）QPPO-40，IEC = 3.59 mmol/g，σ（OH）- = 110.2 mS/cm，在80 ℃）中的高电导率归因于通过SAXS和TEM分析在x（QH）3QPPO膜中观察到的明显的微相分离。此外，x（QH）（3）QPPO样品表现出良好的尺寸特性，（x（QH）（3）QPPO-40在80 ° C下的溶胀率为25.0%）和化学溶胀率为25.0%。（IEC和OH-电导率在1 M NaOH中在80 ℃下30天分别降低22%和25%）稳定性，使得该交联基序适合于燃料电池和其它电化学装置中的潜在膜应用。
Anion exchange membranes (AEMs) are a promising class of materials that enable non-noble metals to be used as catalysts in fuel cells. Compared to their acidic counterparts, typically Nafion and other perfluorosulfonate-based membranes, the low OH- conductivity in AEMs remains a concern as these materials are developed for practical applications. Cross-linked macromolecular structures are a popular way to optimize the trade-off between the ionic conductivity and the water swelling of AEMs with high ion exchange capacities (IECs). However, common cross-linked AEMs (e.g., x(QH)QPPO) that have high degrees of cross-linking with low molecular weight between cross-links are usually mechanically brittle. Moreover, the cross-links in AEMs can hinder the transport of OH-, leading to unsatisfactory conductivities. Here we report a series of elastic and highly conductive poly(2,6-dimethylphenylene oxide) (PPO)-based AEMs(x(QH)(3)QPPO) containing flexible, long-chain, multication cross-links. The strength and flexibility of the x(QH)(3)QPPO samples are significantly improved as compared to the conventional x(QH)QPPO membranes and multication un-cross-linked materials reported previously. The high conductivities in these new materials (x(QH)(3)QPPO-40, IEC = 3.59 mmol/g, sigma(OH)- = 110.2 mS/cm at 80 degrees C) are attributed to the distinct microphase separation observed in the x(QH)3QPPO membranes by SAXS and TEM analyses. Furthermore, the x(QH)(3)QPPO samples exhibit good dimensional (swelling ratio of x(QH)(3)QPPO-40 is 25.0% at 80 degrees C) and chemical (22% and 25% decrease in IEC and OH- conductivity in 1 M NaOH at 80 degrees C for 30 days, respectively) stabilities, making this cross-linking motif suitable for potential membrane applications in fuel cells and other electrochemical devices.