Hybird membrane with high proton conductivity and selectivity based on SPEEK for direct methanol fuel cells

Composite membranes based on sulfonated silica/sulfonated poly(ether ether ketone)(SPEEK) were prepared by means of sol-gel method so as to gain a high conductivity and reasonable methanol permeability. The sulfonated silica is generated in situ via the hydrolysis of sulfonated 3-anminopropyl triethoxysilane(KH550) synthesized newly from 3-aminopropyl triethoxysilane and 1,4-butane sultone. The membrane with a silica mass fraction of 5% exhibits a conductivity of 0.187 S/cm at 80 °C and a methanol coefficient with 9.72×10^-7 cm²/s. The composite membranes show improved condutive ability and better selectivity that can be promisingly used in direct methanol fuel cell.