Multi-imidazolium cationic clusters cross-linked hydrogenated benzonorbornadiene diblock copolymer anion exchange membranes for improving conductivity and mitigating swelling

Abstract

Aiming at insufficient conductivity and excessive swelling of anion exchange membranes (AEMs), the benzonorbornadiene structure was introduced into the backbone and cyclotriphosphazene based hexa-imidazolium cations clusters were adopted. Herein, the multi-imidazolium cations clusters cross-linked hydrogenated benzonorbornadiene diblock copolymer based AEMs were prepared. The combination of multi-imidazolium cations cluster structure and all-hydrocarbon diblock backbone can substantially enhance the self-assembly ability to facilitate microphase separation. The prepared H-rPBenzoNBD-CTPA-MI-1.68 AEM has low swelling ratio (SR = 13.6%), high OH− conductivity (110.0 mS cm−1), and available alkaline stability at 80 °C. It maintains 87.0% of the initial OH− conductivity after 32 days of immersion in 1 M NaOH solution at 80 °C. Moreover, the single cell equipped with H-rPBenzoNBD-CTPA-MI-1.68 AEM obtained a maximum power density of 222 mW cm−2 at a current density of 533 mW cm−2. The multi-imidazolium cations clusters cross-linked hydrogenated benzonorbornadiene diblock copolymer based AEMs have a broad prospect for practical application in fuel cells.