Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units
Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units
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DOI：
10.1021/acssuschemeng.9b05934
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发表时间：
2019-12-16
影响因子：
8.4
通讯作者：
Yoo, Dong Jin
中科院分区：
文献类型：
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作者：
Chu, Ji Young;Lee, Kyu Ha;Yoo, Dong Jin
我们开发了一系列含有砜、酮、六氟异丙基、异丙基、酚酞或亚苯基的杂环季铵型聚亚芳基醚（PAE）无规共聚物，以识别由于聚合物主链结构含有吸电子基团而导致的 AEM 物理化学性质的差异 （EWG）或给电子基团（EDG）。与含有 EWG 的 PYR-PAE 膜相比，含有 EDG 的 1-甲基吡咯烷 (PYR)-PAE 膜表现出更高的氢氧化物电导率，因为离子传输位点分离更明显，这一点通过 AFM 相图得到了证实。所有制备的膜在70℃、2M KOH中700小时的碱性稳定性测试后离子电导率均大于89%，EDG高于EWG的PYR-PAE膜显示出更强的碱性稳定性。特别是，由于空间位阻效应，PYR-PAE-PhPh 膜保留了最高的碱性稳定性，达到 96.9%。在燃料电池运行中，代表EDG的PYR-PAE-PhPh膜表现出比PYR-PAE-BPHF膜（89 mW cm（-2））和商业AEM（[Fumion-FAA-3，30 mW cm（-2））更高的功率密度（109 mW cm（-2））。基于这些结果，我们认为骨架的结构设计是开发具有卓越电化学性能和碱性燃料电池应用碱性稳定性的 AEM 的关键策略。
We developed a series of heterocyclic quaternary ammonium-type poly(arylene ether) (PAE) random copolymers with moieties of sulfone, ketone, hexafluoroisopropyl, isopropyl, phenolphthalein, or phenylene to identify differences in the physicochemical properties of the AEM due to polymer backbone structure containing electron-withdrawing groups (EWGs) or electron-donating groups (EDGs). The 1-methyl pyrrolidine (PYR)-PAE membranes containing EDGs exhibited higher hydroxide conductivity compared with PYR-PAE membranes with EWGs due to more distinctly separated ion transport sites, which was confirmed through AFM phase images. The ionic conductivity of all prepared membranes was greater than 89% after an alkaline stability test for 700 h in 2 M KOH at 70 degrees C, PYR-PAE membranes with EDGs higher than that of EWGs revealed stronger alkaline stability. In particular, the PYR-PAE-PhPh membrane retained the highest alkaline stability of 96.9% due to the steric hindrance effect. In fuel cell operation, the PYR-PAE-PhPh membrane representing EDGs showed a higher power density (109 mW cm(-2)) than that of the PYR-PAE-BPHF membrane (89 mW cm(-2)) and commercial AEM ([Fumion-FAA-3, 30 mW cm(-2)). On the basis of these results, we suggest that structural design of the backbone is a critical strategy to develop an AEM with remarkable electrochemical properties and alkaline stability for alkaline fuel cell applications.