The preparation of novel sulfonated poly(aryl ether ketone sulfone)/TiO2composite membranes with low methanol permeability for direct methanol fuel cells

A sulfonated poly(aryl ether ketone sulfone) (SPAEKS) with locally dense sulfonic acid groups is synthesized and different amounts of TiO(2)is doped into SPAEKS matrix to prepare composite membranes (SPAEKS/TiO2-x). SEM shows that TiO(2)in the composite membranes has good dispersibility when TiO(2)content is not higher than 3%. The composite membranes show good mechanical properties, dimensional stability and oxidative stability. The proton conductivity of composite membranes is near to that of Nafion 117 membrane and methanol permeability of composite membranes is much lower than that of Nafion 117 membrane. Therefore, the proton selectivity of composite membranes is higher than that of Nafion 117 membrane. In particular, proton selectivity of SPAEKS/TiO2-3% (12.8 x 10(4)S s cm(-3)) is four times higher than that of Nafion 117 membrane (3.2 x 10(4)S s cm(-3)).

Automated summary

The composite membranes prepared by doping TiO(2) into SPAEKS matrix exhibit improved proton selectivity while maintaining high proton conductivity, and reduced methanol permeability compared to Nafion 117 membrane.