Anion exchange membranes with dense N-spirocyclic cations as side-chain

Publication date: Available online 11 October 2019Source: Journal of Membrane ScienceAuthor(s): Fang Hua Liu, Qian Yang, Xue Lang Gao, Hong Yue Wu, Qiu Gen Zhang, Ai Mei Zhu, Qing Lin LiuAbstractTo prepare anion exchange membranes (AEMs) with high performances, we tethered the as-synthesized oligomers with dense N-spirocyclic cations (NS) as the side-chain to poly(ether sulfone) (PES). The steric hindrance of spirocyclic structure and electron-donating effect of alkyl spacers significantly enhance the stability of cations in harsh alkaline and high hydration conditions. Correspondingly, the ionic exchange capacity (IEC) of PES–NS–10% only decreased by 13.8% and the conductivity remained 84.3% after being immersed in harsh environment (80 °C, 2 M NaOH) for 864 h. In addition, the high density of N-spirocyclic cations in the side-chain benefits the formation of clear microphase separation, as confirmed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The highest conductivity of 95.5 mS cm-1 was achieved by PES–NS–10% at 80 °C while the corresponding swelling ratio was only 7.69%. Furthermore, the single cell assembled with PES–NS–10% showed a peak power density of 110.1 mW cm-2 at 300 mA cm-2. Durability test of the single cell based on PES–NS–10% under 100 mA cm-2 also demonstrates that the as-prepared AEMs with NS have potential application for fuel cells.Graphical abstract
Source: Journal of Membrane Science - Category: Materials Science Source Type: research