Facilitating ionic conduction for anion exchange membrane via employing star-shaped block copolymer

Anion exchange membrane (AEM) with high ionic conductivity and good stability is of vital importance for developing high-performance alkaline anion-exchange membrane fuel cell (AEMFC). In particular, the performance of AEM largely depends on the microstructure of the basic polymer material. Herein, we have developed a novel strategy to fabricate the AEMs, featuring a star topological structure, via living anionic polymerization and the subsequent functionalization. Thanks to the introduction of well-defined amphiphilic block structure, a distinct micro-phase separation was observed in the synthesized AEMs (AEM-SCP) which were based on star-shaped block copolymers. In comparison to the AEM-LCP membranes based on linear block copolymers, the AEM-SCP membranes exhibited relatively lower water uptake and swelling ratio, but much higher hydroxide conductivity (at 80 °C, 68.1 mS cm−1 for AEM-SCP-3 vs. 38.1 mS cm−1 for AEM-LCP). This is attributed to the efficient aggregation of ionic groups via employing star-shaped block copolymers, which can result in the formation of continuous ion-conducting channels and the facilitated ionic conduction in the AEMs. Furthermore, compared with the AEM-LCP membrane, the dimensional and alkaline stability of the resultant AEM-SCPs have been significantly enhanced.