▎ 摘　　要

Herein, an efficient nanocomposite polymer electrolyte membrane has been designed by the synergistic com-bination of graphene oxide and SiO2 by following a facile and cost-effective in-situ synthesis method. The suc-cessful formation and covalent attachment of the SiO2 nanoparticles over the G surface have been validated from FTIR, XRD, Raman and TGA studies. The surface morphologies with even dispersion capacity and particle size of the synthesized nanoparticles were also studied from FESEM-EDS, TEM, and particle size analyser, respectively. Then the GS/PVDF-co-HFP nanocomposite membranes were prepared via solution casting followed by func-tionalization with chlorosulfonic acid. These new sulfonated PVDF-co-HFP-based SiO2-covered graphene oxide nanocomposite membranes (SPCGS) had improved properties attributing to increased water absorption, ion exchange capacities, and increased proton conductivities. Further, the barrier effect rendered by the GS nano -particles assists in decreased methanol permeability of the SPCGS membranes due to the tortuosity of the methanol flow channels. The potentiality of the membrane was further assessed from chemical structure analysis, and morphological, thermal, and mechanical analyses like FTIR, NMR, XRD, FESEM-EDS, TGA and UTM, etc. Interestingly, the membrane selectivity has been enhanced up to 3.58 x 10(5) S.scm(-3) thereby depicting the potentiality of SPCGS membranes in DMFC.