Proton conducting membranes based on sulfonated poly(ether ether ketone)/TiO2 nanocomposites for a direct methanol fuel cell

This paper presents an evaluation of the effects of titanium dioxide nanoparticles in sulfonated poly(ether ether ketone) (SPEEK) with a sulfonation degree of 57%. A series of inorganic/organic hybrid membranes was prepared with a systematic variation of titanium dioxide nanoparticle content. Their water uptake, methanol permeability and proton conductivity as a function of temperature were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increasing the inorganic oxide content leads to a decrease of methanol permeability. In terms of morphology, the membranes are homogeneous and exhibit good adhesion between inorganic domains and the polymer matrix. The proton conductivity and fuel cell performances of the nanocomposite membranes showed very good prospective in direct methanol fuel cell usages. The properties of the composite membranes are compared with those of standard Nafion membranes. (c) 2006 Society of Chemical Industry.