Constructing high temperature proton exchange membranes with sandwich structure based on graphene oxide nanosheets and electrospinning polyvinyl chloride nanofibers

Abstract

Graphene oxide (GO) nanosheets were believed to possess the merits of extraordinary mechanical property, wide surface area and low price, etc. Polyvinyl chloride (PVC) nanofibers were prepared through the electrospinning technique and combined with GO nanosheets to construct the (PNs/GO/PNs)es membrane with sandwich structure. Furthermore, imidazolium-GO (ImGO) nanosheets were synthesized through the cations of imidazolim-based ionic liquids grafting GO nanosheets. In the prepared membranes, GO and ImGO nanosheets functioned as proton conduction carriers and combined phosphoric acid (PA) molecules with intermolecular hydrogen bonds. The outer PVC nanofibers mats protected the inner GO nanosheets layer and served as an efficient proton conduction media. On the basis of it, the prepared PA doped membranes possessed the improved proton conductivity and enhanced mechanical property, deriving from fast proton conduction and compact structure. Specifically, (PNs/GO/PNs)es/PA and PVC/ImGO/PA membranes exhibited the maximum proton conductivities of 9.26 × 10−2 S/cm and 2.63 × 10−2 S/cm at 150 °C. The residual values were respectively 9.02 × 10−2 S/cm and 3.41 × 10−2 S/cm after a 384 h non-stop at 120 °C. Notably, the tensile stress of the (PNs/GO/PNs)es/PA membrane reached 11.6 MPa, higher than 7.11 MPa of the (PNs/GO/PNs)es membrane. The research revealed that GO and ImGO nanosheets promoted proton conduction through combining PA molecules with the reduction of proton conduction resistance in high temperature proton exchange membranes (HTPEMs).