Proton-conducting hybrid membranes consisting of poly(ether ether ketone) sulfonated (SPEEK) and titanium oxide (TiO2) were prepared using the sol-gel technique for application in direct ethanol fuel cells. The effect from TiO2 incorporation on membrane properties such as ethanol uptake, pervaporation and proton conductivity was investigated. The uptake and permeated flux decreased with increasing content of TiO2. The ethanol permeability was about one order of magnitude smaller than Nafion® 117. FTIR spectra indicated that PEEK was sulfonated and the second degradation temperature of SPEEK58 samples confirmed the titanium oxide incorporation. The proton conductivity in ethanol solution was of the order of 10-3 S cm-1 when 4 or 8 wt% TiO2 were added, and generally increased with addition of TiO2.
Poly(ether ether ketone); sulfonation; titanium oxide; DEFCs
