Polyethylene terephthalate/poly (vinylidene fluoride) composite separator for Li-ion battery

Electrospun nanofiber membranes have been proved to enhance performances of Li-ion batteries, but their poor mechanical strength hinders their industrial application. This paper combines meltblown polyethylene terephthalate (PET) nonwoven and electrospun poly (vinylidene fluoride) (PVDF) membrane together to improve the mechanical property via hot-pressing, wherein a dried 3 wt% PVDF solution coating on PET nonwoven is used as a binder. The hot-pressing temperature is optimized to be 145 °C and the composite PET/PVDF separator exhibits an excellent mechanical property, whose transverse and longitudinal tensile strength could reach 13.70 and 34.85 MPa respectively. Compared with a commercial PP separator, the hot-pressed PET/PVDF membrane separator shows better wettability, higher thermal shrinkage and improved electrochemical performance as well.