Alkali-resistant poly (vinyl benzyl chloride) based anion exchange membranes with outstanding flexibility and high hydroxide ion conductivity

Preparing AEMs with robust mechanical properties, high ionic conductivity and excellent chemical stability is challenging. Here, cross-linked/aggregated AEMs are prepared by incorporating hydrophilic Jeffamine cross-linkers and hydrophobic side chains into the rigid quaternized poly (vinyl benzyl chloride). Jeffamine's flexibility ensures high elongation at break of the cross-linked/aggregated membranes (125.0–199.8%). The hydrophobic side chain limits excessive water absorption and facilitates self-aggregation of hydrophilic and hydrophobic domains, enhancing tensile strength (5.08–7.40 Mpa in wet state) and improving ionic conductivity of the AEMs (73.8–110.4 mS cm−1 at 80 °C). Alkali-resistant PVB, restricted dimensionality, and ordered micro-phase separation morphology contribute to outstanding chemical stability of the AEMs. Degradation of both backbones and cations is <20% after treatment in 1 M NaOH solution at 80 °C for 30 days. Based on the membrane, a peak power density of 354.4 mW cm−2 at 60 °C is yielded.