Can the variation in hydrophobic side chain types enhance the comprehensive performance of anion exchange membrane fuel cells?

Developing anion exchange membranes (AEMs) with simultaneous high ion conductivity and durability remains critical prerequisites for high performance fuel cell commercialization. Rational design of hydrophobic side chains has recognized as an effective approach to enhance ion transport in the AEMs through obvious microphase separation. Herein, we systematically design a series of AEMs with structurally tailored hydrophobic side-chain engineering strategy to boost both conductivity and stability. Moreover, the effects of hydrophobic side chain types on the AEM performance were thoroughly contrasted through a comprehensive investigation. Among them, the membrane 6BHC-FPhe-TMA incorporating mono-fluorine substituted alkoxy-phenyl hydrophobic side chains exhibit well-defined microphase separation, enabling exceptional high hydroxide conductivity of 161.06 mS cm −1 at 80 °C with low ion exchange capacity (1.37 mequiv. g −1 ) while maintaining controlled swelling ratio (14.08 %). Remarkable alkaline stability is evidenced by 93.24 % conductivity retention after 1344 h alkaline treatment (2 M NaOH, 80 °C). When integrated into H 2 /O 2 fuel cell, the membrane delivers a peak power density of 522 mW cm −2 and reveals outstanding durability with negligible voltage decay (0.16 mV h −1 ) during 72 h operating at 100 mA cm −2 . This work provides a novel materials design paradigm combing fluorine substituted alkoxy-phenyl side chain, offering significant progress toward practical AEMFCs applications.