Fabrication and electrochemical properties of highly selective SPES/GO composite membranes for direct methanol fuel cells

Graphene oxide (GO) was synthesized and used as an additive at various proportions with the intention of fabrication of sulfonated poly (ether sulfone) (SPES) based composite proton exchange membranes (PEMs) for direct methanol fuel cell (DMFC) applications. Among the various composite membranes prepared, SPES/GO (1 wt%) was found to have the highest selectivity with a water uptake of 40.1%, proton conductivity of 4.3 x10(-3) S/cm, and methanol permeability of 4.923 x10(-8) cm(2)/s. The introduction of GO in membranes not only improved proton conductivity, but also positively affected the mechanical properties and the blocking of methanol molecules passing through the membrane. Consequently, the incorporation of GO into SPES membrane has considerably increased the selectivity of the membrane. Therefore, SPES/GO membranes showed three folds increase in performance than original SPES membrane, and hence acted as a good candidate for use in DMFC in order to resolve current issues of methanol crossover.