Alkaline anion-exchange polymer membrane with grid–plug microstructure for hydrogen fuel cell application

Porous polysulfone membrane, prepared by a phase-inversion technique, is filled with (3-acrylamidopropyl)trimethylammonium chloride and N,N′-methylenebisacrylamide via interfacial diffusion. The impregnated membrane is then subjected to UV-irradiation for polymerizing monomers that are entrapped in pore channels of the membrane. This in-situ polymerization engenders a grid–plug microstructure, where the grid is polysulfone and the plugs are an ion (OH−) conducting phase. As the plugs are extensively interconnected and non-tortuous throughout the membrane matrix, the ion-conducting phase sustains a power density as high as 55 mW cm−2 at 60 °C. Thermal analysis indicates that the pore-filling condition affects the packing density of the plugs that in turn, impacts on ion transport flux.

Research highlights
► An alkaline anion-exchange membrane with a grid (structural component)–plug (electrolyte component) microstructure is fabricated by the approach consisting of pore-filling and in-situ polymerization steps.
► The ionic conducting plugs are interconnected throughout the entire matrix of membrane.
► This dual continuous-phase structure ensures both good mechanical properties and ionic conductivity.
► The resulting membrane exhibits a maximum power density of 55 mW cm−2 at 60 °C.