Crosslinked high-performance anion exchange membranes based on poly(styrene-b-(ethylene-co-butylene)-b-styrene)

Development of anion exchange membranes with good dimension, chemical stability, high conductivity and long life-time simultaneously is still a challenge for practical application of anion exchange membrane fuel cells. Herein, a mechanically and chemically stable poly(styrene-b-(ethylene-co-butylene)-b-styrene) triblock copolymer based crosslinked membranes are designed, prepared and characterized. N,N,N′,N′-tetramethyl-1,6-hexanediamine is introduced into the membranes as the crosslinker and functional reagent, which exhibits the significant improvement in water uptake (less than 7%), swelling ratio (8–5%, greatly smaller than uncrosslinked membranes) and tensile strength (higher than 18 MPa). The hydroxide conductivity (14.9 mS cm−1 at 30 °C) of the obtained membrane is obtained due to hydrophilic/hydrophobic microphase separation formed between the structure of crosslinking and quaternary ammonium groups. It demonstrates that incorporating stable crosslinking structure to polymer backbone greatly improves the chemical stability under Fenton and alkaline long-term tests. Furthermore, the peak power density of an H2/O2 single fuel cells reaches high peak power density of 416 mW cm−2 at 0.514 V. Based on these outstanding properties, the developed crosslinked membranes will be a promising candidate material for anion exchange membrane fuel cells.