Anion Exchange Membrane and Manufacturing Method Thereof

Highly Durable Anion Exchange Membrane Based on Long-Chain Alkyl Side Chains and Physical Cross-Linking Additives

This technology involves creating an anion exchange membrane by introducing long alkyl chains (C8–C18) and quaternary ammonium groups (ion-conducting groups) into the side chains of a polymer backbone, then adding physical cross-linking agents such as ammonium, imidazolium, or piperidinium salts. The manufacturing process includes acylation, reduction, chloromethylation, quaternary ammonium introduction, and additive incorporation.

Anion exchange membranes for alkaline fuel cells have historically faced a trade-off: increasing the ion exchange capacity (IEC) to improve conductivity leads to higher water uptake and weakened mechanical properties, while lowering the IEC significantly reduces conductivity. Furthermore, rapid chemical degradation in high-temperature alkaline environments has made it difficult to ensure long-term operational stability.

This technology uses long alkyl side chains to create hydrophobic regions that align ion channels, while 5–20 parts by weight of salt additives per 100 parts of polymer form physical cross-links between chains, ensuring both high ion conductivity and chemical stability. Alkaline fuel cells using this membrane show significantly improved lifespan. It can be applied to hydrogen fuel cell vehicles and electrochemical device separators, enhancing the practical durability of alkaline fuel cells that rely less on precious metal catalysts.

‍

‍

Key Features:

• A polymer for anion exchange membranes represented by Formula 1, containing alkyl groups with 8 to 18 carbon atoms and side chains with quaternary ammonium groups
• An anion exchange membrane comprising the polymer of Formula 1 and at least one additive selected from ammonium, morpholinium, guanidinium, imidazolium, piperidinium, phosphonium, and sulfonium salts
• A configuration containing 5 to 20 parts by weight of the additive per 100 parts by weight of the polymer, with the membrane applied to fuel cells, electrochemical devices, and transportation vehicles
• A method for manufacturing an anion exchange membrane by acylating and reducing a raw polymer to introduce alkyl groups, followed by chloromethylation, introduction of quaternary ammonium, and addition of the additive

‍

This invention was developed with support from the Ministry of Science and ICT for the development of core materials for high-performance anion-exchange membranes through molecular structure control.

‍