Self-aggregating anion exchange membrane with a comb structure

Fuel cell anion exchange membrane with enhanced hydroxide ion conductivity using a comb-shaped structure with long-chain alkyl side chains

This technology features a self-aggregating anion exchange membrane with a comb-like structure, where OH- conductive side chains, such as C6-C16 alkyl imidazoles, are attached to a polymer backbone like poly(arylene sulfone). The long alkyl chains create hydrophobic regions that aggregate ion clusters and form widely connected ion channels.

Anion exchange membranes for alkaline fuel cells have traditionally used quaternary ammonium cations, which degrade easily at high pH, while imidazolium-based alternatives have lacked sufficient conductivity. Increasing the ion exchange capacity to boost conductivity often led to excessive water absorption and significant membrane swelling.

This technology maintains an ion exchange capacity of 0.92–1.14 meq/g while enhancing ion mobility to achieve hydroxide ion conductivity exceeding 0.14 S/cm at 80°C, along with excellent chemical, thermal, and dimensional stability. It can be applied to membranes in alkaline exchange membrane fuel cells (AEMFC) and water electrolyzers using non-precious metal catalysts, enabling membrane designs that reduce stack material costs while maintaining high-temperature performance.

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Key Features:

• Comb-structured anion exchange membrane with at least one OH- conductive side chain—selected from alkyl imidazole, alkyl guanidinium, alkyl phosphonium, or alkyl ammonium—bonded to a polymer backbone
• Configuration forming self-aggregating ion channels by setting the number of carbons in the alkyl group of the OH- conductive side chain to 6–16
• Configuration where the poly(arylene sulfone) backbone is synthesized by polymerizing OH-terminated and F-terminated oligomers with a degree of polymerization of 13, followed by the attachment of alkyl imidazole side chains
• Anion exchange membrane with a thickness of 30–50㎛, an ion exchange capacity of 0.92–1.14 meq/g, and a hydroxide ion conductivity of 0.14 S/cm or higher at 80°C

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