Helical configuration channels boost performance in anion exchange membranes

Herein, anion exchange membranes (AEMs) containing biomimetic helical conduction channels are prepared. The helical structures can construct columnar ion transport channels and the helical cavities serve as the water storage spaces, which simultaneously enhance the conduction and water retention properties. Molecular simulation, circular dichroism (CD) spectra and water sorption/desorption verify that piperidinium cations are ordered around helical polymers to form ion transport channels and the helical cavities have strong water retention capacity. Among all the prepared membranes, the AEM (40 %-PPT-c-PmpP) containing the maximum helical polymers exhibits the highest OH− conductivity (148.6 mS cm−1 @ 80 °C) with the lowest ion exchange capacity (IEC). Meanwhile, the decreased H2/O2 single cell performance based on 40 %-PPT-c-PmpP is the lowest (only 4.8 %) as the relative humidity (RH) drops to 70 %, due to its highest water retention properties. The 40 %-PPT-c-PmpP AEM exhibits excellent alkaline stability (96.8 % and 98.2 % of the initial OH− conductivity and IEC retained after being treated into 1 M NaOH at 80 °C for 3000 h separately). These results indicate that constructing the helical conduction channels is a promising tactic for obtaining high performance AEMs.