SPVdF-HFP/SGO nanohybrid proton exchange membrane for the applications of direct methanol fuel cells

Abstract

Sulfonated poly (vinylidene fluoride-co-hexafluoropropylene) (SPVdF-HFP)/sulfonated graphene oxide (SGO) hybrid membrane was prepared via solution casting process. Incorporation of SGO nanosheets into SPVdF-HFP matrix increases the density of sulfonic acid moieties of hybrid membrane. This offer better water uptake, good proton conductivity, than pristine SPVdF-HFP membrane. Additionally, the complex structure generated between SGO and membrane chains helps to reduce methanol uptake and swelling ratio of the hybrid membrane. The formation of electrostatic interaction between membrane backbone and SGO skeleton helps the SPVdF-HFP/SGO to retained lower weight loss than SPVdF-HFP during TGA analysis. The presence of SGO nanosheets in membrane matrix is confirmed by morphological studies. The SPVdF-HFP/SGO membrane achieved maximum proton conductivity of 7.8 mS/cm at 70 °C and low methanol permeability of 2.567 × 10−7 cm2/s at 70 °C whereas the pristine SPVdF-HFP membrane exhibits 1.7 mS/cm and 3.105 × 10−7 cm2/s. From the obtained good results of hybrid membrane, we believe that the SPVdF-HFP/SGO would be a promising candidate for the application of DMFCs.