Polymer electrolyte membranes (PEM) prepared by radiation-induced graft copolymerization are investigated. For this purpose, commercial poly(ethylene-alt-tetrafluoroethylene) (ETFE) films were activated by electron beam treatment and subsequently grafted with the monomers glycidyl methacrylate (GMA), hydroxyethyl methacrylate (HEMA) and N,N′-methylenebis(acrylamide) (MBAA) as crosslinker. The target is to achieve a high degree of grafting (DG) and high proton conductivity. To evaluate the electrochemical performance, the PEMs were tested in a fuel cell and in a vanadium redox-flow battery (VRFB). High power densities of 134 mW∙cm−2 and 474 mW∙cm−2 were observed, respectively.
Polymer electrolyte membranes (PEM) for potential applications in fuel cells or vanadium redox flow batteries were synthesized and characterized. ETFE (poly (ethylene-alt-tetrafluoroethylene)) and PVDF (poly (vinylidene fluoride)) serving as base materials were activated by electron beam treatment with doses ranging from 50 to 200 kGy and subsequently grafted via radical copolymerization with the functional monomers 2-acrylamido-2-methylpropane sulfonic acid and acrylic acid in aqueous phase. Since protogenic groups are already contained in the monomers, a subsequent sulfonation step is omitted. The mechanical properties were studied via tensile strength measurements. The electrochemical performance of the PEMs was evaluated by electrochemical impedance spectroscopy and fuel cell tests. The proton conductivities and ion exchange capacities are competitive with Nafion 117, the standard material used today.
Proton exchange membranes for high temperature fuel cell applications were obtained via graft copolymerizations on commercial poly(ethylene-alt-tetrafluoroethylene) (ETFE) films. ETFE was activated by electron beam treatment, and the hydrophilic monomers acrylic acid and hydroxyethyl methacrylate were grafted to ETFE. The maximum grafting level was 620%. The grafted membranes were doped with the proton carrier phosphoric acid leading to a maximum doping level of 450%. Stress-strain measurements indicate good mechanical stability of the composite membranes. The polymer-acid membranes were tested in a H 2 /O 2 fuel cell. At a current density of 200 mA Á cm À2 a stable power density of 113 mW Á cm À2 was determined at 120 8C. The results show that high phosphoric acid contents associated with high proton conductivity may be obtained with a copolymer containing acrylic acid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.