PPESK/PVDF Lithium-ion Battery Composite Separators Fabricated by Combination of Electrospinning and Electrospraying Techniques

In order to improve the mechanical property of traditional electrospinning fibrous membranes, PPESK-fiber/PVDF-bead composite membranes were prepared via simultaneously electrospinning of PPESK concentrated solution and electrospraying of PVDF dilute solution, and then hot pressed at 160℃. The membrane structure, tensile strength, ionic conductivity and cycling performance of lithium-ion batteries were measured by scanning electron microscope, universal tensile test machine, electrochemical work station and battery cycle system. The results show that the hot-pressed PPESK/PVDF composite membrane separator exhibits excellent liquid electrolyte wettability, ionic conductivity reaches 1.92mS·cm-1 at room temperature,PVDF beads are uniformly dispersed in PPESK fibers. The interfacial strength of PPESK fibers is effectively enhanced due to the melt of PVDF beads during the hot press process, hence the mechanical strength of composite membrane is leached 13.2MPa. In addition, cells assembled with PPESK/PVDF composite membrane show high discharge capacity and stable cycling performances.