Jinlei Wang, Xiaojuan Wang, Daoyuan Zu
2018
Citations
0
Influential Citations
36
Citations
Journal
Journal of Membrane Science
Abstract
Abstract In the pursuit of alkaline stable cationic ions as promising candidates for high performance anion exchange membranes, two novel imidazoliums with N3-adamantyl substituent along with four imidazoliums with N3-methyl and butyl-substituents were synthesized and systematically assessed the impact of N3- and C2-substitutions on their chemical stabilities. Substituent at the N3-position prevented the degradation of imidazolium, and bulky and rigid adamantyl substituent was the most effective. The 1-adamantyl-2-methyl-3-ethylimidazolium cation ( AdMEIm ) exhibited the highest alkaline stability among the six cationic ions, which is stable under 5 M NaOH aqueous solution at 80 °C for 168 h. Combined with the highly chemical stability of N3-adamantyl substituted imidazolium and excellent chemical and thermal stability of poly(2,6-dimethyl phenylene oxide) (PPO), the PPO-based AEMs functionalized with N3-adamantyl substituted imidazolium were further synthesized and characterized. However, unlike the small-molecule imidazolium salt with exceptional alkaline stability, a considerable ring-opening degradation of imidazolium was taken place for AEM functionalized with the stable N3-adamantyl substituent when exposed to 1 M NaOH aqueous solution at 60 °C for over 48 h, demonstrating that the alkaline stabilities of modular cation and the corresponding AEM seems less correlated. A single H 2 -O 2 fuel cell using PPO-AdIm-34 membrane showed a peak power density of 46.0 mW cm −2 and an open circuit voltage (OCV) of 0.90 V at 45 °C without any optimization of the electrodes, demonstrating that the as-prepared membranes have potential application in AEMFCs.