Fabrication and characterization of reinforced electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofiber membranes

In this study, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membranes with different amounts of polyethylene glycol (PEG) and polyethylene glycol dimethacrylate (PEGDMA) oligomer were fabricated via electrospinning. The obtained nanofiber membranes were subsequently thermal treated to produce physically bonded structures and chemically cross-linked networks, which were confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and wide-angle X-ray diffraction (WAXD). Young's modulus of electrospun nanofiber membrane with the composition of PVDF-HFP/PEG/PEGDMA (6/1/3, w/w/w) was approximately three times for the case of nanofiber membrane and four times for the case of single nanofiber higher than that of pure PVDF-HFP nanofiber, respectively. The characteristic of cell cycling performance was demonstrated as the possibility of its application at ambient temperature. The electrospun PVDF-HFP nanofiber membrane presented great electrolyte uptake because the membrane had higher porosity due to the structural features of nonwoven fabric, and the amorphous regions in PVDF-HFP could trap large amounts of liquid electrolyte. Also, the cell performance of the membrane as the separator declared high discharge capacity. As the result, the reinforced electrospun composite nanofiber membrane was found to be a promising candidate as a separator for lithium-ion batteries.