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Anion exchange membranes (AEMs) are widely studied as an important component of fuel cells. In this paper, series self-crosslinking AEMs are obtained by copolymerization of the prepared bis-imidazolium functionalized ionic liquids. The block copolymer shows excellent thermal stability with a decomposition temperature (Td) of 300 °C. And the mechanical properties of AEMs in OH− are significantly improved due to the crosslinking of epoxy groups. The transmission electron microscopy (TEM) test results show a good microscopic phase separation structure and form ion channels in the membranes, which is benefited to ions conductivity. The OH− conductivity of AEMs is measured as above 24 10 − 3 S cm − 1 and 95 10 − 3 S cm − 1 at 30 °C and 80 °C, respectively. In addition, the AEMs also exhibits excellent swelling performance, the highest is only 20.86% at 80 °C. And the conductivity of all AEMs remained above 90% after being immersed in 1 M NaOH aqueous at 60 °C for 250 h. The peak power density of the AEMs reaches 207.95 mW cm−2 at current density of 403 mA cm−2. • A kind of bis-imidazolium functionalized norbornene ionic liquid was synthesized. • The resulting membranes exhibit excellent anti-swelling and mechanical properties. • The resulting membranes exhibit high ionic conductivity and peak power density. [ABSTRACT FROM AUTHOR]

We incorporate epoxy group functionalized side chain and imidazolium-terminated flexible side chain to norbornene copolymer backbone result in forming a space cross-linked topological structure for alkaline anion exchange membrane (AAEM). The introduction of epoxy groups to the copolymer backbone gives it some special properties, such as good solubility in ordinary organic solvent and the formation of self-cross-linked structure under alkaline environment without additional cross-linker or initiator. The as-prepared copolymers show excellent thermal stability (Td > 320 °C). The self-assembly of hydrophilic flexible side chains and hydrophobic polymer backbone result in well-defined micro-phase separation. The hydroxide conductivity of AAEMs as high as 90 mS cm−1 at 80 °C and after 10 days in 2 M NaOH aqueous at 60 °C the hydroxide conductivities of membranes only decreased by 25%. A peak power density of 118.4 mW cm−2 at a current density is 253.1 mA cm−2 is demonstrated. Image 1 • Epoxy group and imidazolium group with flexible side chain were incorporated into norbornene-based copolymer for AAEMs. • The AAEMs show a well-defined microscopic phase separation structure. • The AAEMs formed self-cross-linked topological structure under high pH conditions. • The hydroxide conductivity was measured as high as 90.0 mS cm−1 at 80 °C.. [ABSTRACT FROM AUTHOR]