Hybrid Poly(ionic liquid) Membranes with in Situ Grown Layered Double Hydroxide and Preserved Liquid Crystal Morphology for Hydroxide Transport

Recently, alkaline polymer electrolytes have obtained widespread attention because of their increasing application for energy storage and conversion systems. In this work, a novel poly(ionic liquid) membrane preserving liquid crystal (LC) nanostructures composited with layered double hydroxide (LDH) was constructed. The LDH is in situ synthesized using hexagonal LC as a nanoreactor and exhibits a hierarchical structure in the membrane. The preserved LC nanostructures and in situ grown LDHs in the LC phase provide organic and inorganic pathways for hydroxide transport. The formation of continuous hydrogen bond networks among the hydroxide groups on the surface of LDHs distributed in hexagonal mesophases, and the positively charged imidazolium groups of the poly(ionic liquid) backbone lead to a high hydroxide conductivity according to the Grotthuss mechanism. Meanwhile, the hybrid membrane also exhibits a low swelling degree, enhanced chemical stability, and a comparable mechanical property. The novel combination of in situ synthesized LDHs and LC nanostructures in a poly(ionic liquid) film provides a feasible method to develop hybrid anion exchange membranes (AEMs) with enhanced performances.