4(5)-vinylimidazolium based anion-conducting electrolyte membrane prepared by radiation-induced grafting for hydrazine hydrate fuel cell

Yoshimura, Kimio; Koshikawa, Hiroshi; Yamaki, Tetsuya; Shishitani, Hideyuki*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Maekawa, Yasunari

Anion-conducting electrolyte membrane fuel cells (AEMFCs) especially in direct hydrazine fuel cells have recently received considerable attention. Due to high temperature and highly basic operating condition, it is required to develop alkaline durable AEMs. In this work, we synthesized the AEM based on a 4(5)-vinylimidazole (4VIm) monomer by radiation-induced grafting and subsequent -alkylation and ion exchange reactions () because 4VIm does not possess -protons, leading to a Hoffman elimination reaction, which is the main degradation route in 1-vinylimidazolium-grafted AEM (). The alkaline stability of AEMs was estimated by monitoring the change in conductivity of AEMs in 1 M KOH at 60C. As a result, the conductivity of suddenly decreased within few hours, while the initial decrement of conductivity of was clearly suppressed. It clearly showed that the prevention of a Hoffman elimination reaction enhanced the alkaline durability of the imidazolium-type AEM.