Anion exchange membrane electrolyte preserving inverse Ia3‾d bicontinuous cubic phase: Effect of microdomain morphology on selective ion transport

The understanding of structure-morphology-property relationships is pivotal in the rational design of ion-exchange membranes with well-balanced properties. Prior observations have led to the general perception that well-defined hydrophilic/hydrophobic phase-segregated morphologies are relevant for efficient ion transport. On this basis, herein, the membrane microdomain morphology, along with its ion transport mechanisms, are discussed with respect to permselectivity. We propose and demonstrate a simple approach to construct liquid-crystalline anion-exchange membrane preserving inverse bicontinuous cubic structure. The resulting membrane exhibits improved hydroxide conductivity, superior water management ability, and enhanced alkaline stability. More importantly, the preserved 3D-interconnected ion channels selectively transport hydroxide via a reduced migration barrier, while inhibiting crossover of hydrated ions and organic solutes. These results highlight the outstanding potential of cubic liquid crystal mesophases as an attractive material for designing membranes with well-defined ion channels, while offering mechanistic insights into the structure-morphology-property relationships of membrane electrolytes for advanced energy applications.