Highly Stable, Anion Conductive, Comb-Shaped Copolymers for Alkaline Fuel Cells
Highly Stable, Anion Conductive, Comb-Shaped Copolymers for Alkaline Fuel Cells
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DOI：
10.1021/ja403671u
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发表时间：
2013-07-10
影响因子：
15
通讯作者：
Wang, Chao-Yang
中科院分区：
文献类型：
--
作者：
Li, Nanwen;Leng, Yongjun;Wang, Chao-Yang
为了制备一种用于碱性燃料电池的负离子导电、耐用的聚合物电解液，利用孟休金反应合成了一系列含有长烷基侧链的聚(2，6-二甲基苯氧基)S季铵盐，形成梳状结构。小角X射线散射(SAXS)结果表明，侧链是形成高导电性离子结构域的主要原因。具有一个烷基侧链的梳形聚合物的氢氧化物导电性高于那些具有一个以上烷基侧链结构或每个阳离子中心含有一个以上烷基侧链的梳状聚合物。结果表明，含有苄基二甲基十六烷基铵阳离子的梳状聚合物的电导率最高。在严重的加速老化条件下对梳状膜的化学稳定性进行了评价，并通过测量老化过程中离子交换容量和离子电导率的变化来观察其降解情况。这些阳离子聚合物在80℃的1M氢氧化钠中保持了较高的离子导电性，在碱性燃料电池的催化层中被用作离聚体。结果表明，尽管C-16烷基侧链离聚体的IEC值较低，但其初始性能略好，但在燃料电池中的耐久性很差。相比之下，含C-6侧链电极的碱性燃料电池在运行60h后仍保持了90%的初始性能。
To produce an anion-conductive and durable polymer electrolyte for alkaline fuel cell applications, a series of quaternized poly(2,6-dimethyl phenylene oxide)s containing long alkyl side chains pendant to the nitrogen-centered cation were synthesized using a Menshutkin reaction to form comb-shaped structures. The pendant alkyl chains were responsible for the development of highly conductive ionic domains, as confirmed by small-angle X-ray scattering (SAXS). The comb-shaped polymers having one alkyl side chain showed higher hydroxide conductivities than those with benzyltrimethyl ammonium moieties or structures with more than one alkyl side chain per cationic site. The highest conductivity was observed for comb-shaped polymers with benzyldimethylhexadecyl ammonium cations. The chemical stabilities of the comb-shaped membranes were evaluated under severe, accelerated-aging conditions, and degradation was observed by measuring IEC and ion conductivity changes during aging. The comb-shaped membranes retained their high ion conductivity in 1 M NaOH at 80 degrees C for 2000 h. These cationic polymers were employed as ionomers in catalyst layers for alkaline fuel cells. The results indicated that the C-16 alkyl side chain ionomer had a slightly better initial performance, despite its low IEC value, but very poor durability in the fuel cell. In contrast, 90% of the initial performance was retained for the alkaline fuel cell with electrodes containing the C-6 side chain after 60 h of fuel cell operation.