Zirconium oxide modified sulfonated poly(ether either ketone) membranes for direct methanol fuel cell applications

Abstract

In order to perform a critical analysis of the zirconium oxide effects in sulfonatedpoly(ether ether ketone) (SPEEK) membranes with two sulfonation degrees (SD), 71 and 87%, thecharacterization of composite membranes prepared with a systematic variation of the inorganiccontent is proposed. The method involves preparation of inorganic composite membranes with awide range of properties which concern water swelling, chemical and thermal stability, methanoland water permeations and, finally, proton conductivity. A good balance between high protonconductivity, good chemical stability and low methanol permeability is reached for the SPEEKpolymer with a 7.5% (w/w) ZrO2 content and SD=87%. Compared to NAFIONÆ 112, thismembrane is 3-times more selective towards water/methanol permeation and has a similar protonconductivity (81 compared to 88 mS/cm).