Radiation-induced grafting for proton- and anion-conducting polymer electrolyte membranes in fuel cell applications

Maekawa, Yasunari

Radiation-induced grafting technique was applied to the development of proton- and anion-exchange membranes (PEM and AEM) for hydrogen- and alkaline hydrated hydrazine-fuel cells (FCs). For PEM, mechanically and thermally stable poly(ether ether ketone) (PEEK) film could be converted to graft-type PEMs (PEEK-PEMs), which showed superior conductivity and tensile strength under low and high RH conditions than those of Nafion, Accordingly, the PEEK-PEMs with high IEC values possesses both superior conductive and mechanical properties. In contrast, by introducing poly(vinylimidazolium hydroxide) (PVIm) as an anion exchange group using radiation grafting, poly(ethylene-co-tetrafluoroethylene) (ETFE) could be converted to ETFE-AEMs, exhibiting higher anion conductivity and alkaline stability than commercial AEMs. We proved that moderate basicity and dissociation properties of PVIm were important characteristic for conductivity and alkaline stability.