Preparation and characterization of a polyvinyl alcohol grafted bis-crown ether anion exchange membrane with high conductivity and strong alkali stability

Abstract A new type of symmetrical bis-crown ether is prepared by connecting dibenzo-18-crown-6 ether on both sides of the chromotropic acid, and then grafting the aforementioned bis-crown ether onto polyvinyl alcohol matrix to prepare a series of anion exchange membranes (AEMs), which their have high conductivity and strong alkali stability. These synthesized membranes were named B-CX%-P AEMs (x is the mass percentage of the symmetrical bis-crown ether (B–C)). Then, the chemical structure of aforementioned AEMs were verified by means of 1H NMR, FT-IR and UV. Meanwhile, the OH− conductivity, alkaline stability and single cell performance of the synthesized membrane were also investigated. The results revealed that the conductivity of B–C30%-P membrane is the highest at 80 °C (235 mS cm−1), and the power density is also the highest (197 mW cm−2), and the alkali stability of the membrane synthesized in this paper was also improved. The conductivity at 80 °C was only reduced by 4%, which was obtained by immersing the B–C30%-P membrane immersed in 6 mol L−1 KOH solution for 168 h, which the aforementioned results proved that the synthesized membrane in this research had excellent OH− conductivity and alkaline stability.