Research Of Nozzleless Electrospinning Equipment And Its Application In Preparation Of Separator Based On PVDF

Nanofibers have excellent small size effect including high porosity, high specific surface area, Therefore, nanofibers are widely used in the field of new energy materials. The porosity and electrolyte absorption of separator prepared by electrospinning are more excellent than conventional preparation method. Electrospinning is more suitable for industrial production, because its simple operation and low price. But, low yield is the development bottleneck electrospinning. Designing new spinning equipment is a necessary requirement for development of materials.In order to increase yield of electrospinning, we invented no nozzle electrospinning equipment that can continuously work.The poly(vinylidene fluoride)(PVDF) membrane was prepared by phase inversion in this paper. In order to improve the properties of the film, a layer of PVDF-PMMA nanofiber is laid on both sides of membrane by electrostatic spinning technique. And the membrane were characterized and electrochemical performance testing.According to the basic principle of electrostatic spinning technique, electrostatic spinning machine with arc nonwoven as receiving apparatus is made. PVA is used for electrospinning test using equipment developed. According to the results, the influence of various experimental parameters on the fiber morphology was analyzed. Results showed that the threshold voltage of the spinning device is about 62 k V, the greater voltage, the greater the velocity of the jet,fibers is vulnerable to block; the jet of low-concentration solution, which is the molecular chain entanglement is not tight enough, the fibers are easily broken. The optimum concentration was about 10% in this experiment. Mobile receiving apparatus is equivalent to improve the reception distance, which provides ample time and space conditions for solvent evaporation and jet stretch, The mutual adhesion between the fibers is prevented, In this experiment, the optimum moving speed of the receiving device is about 30r/min. Rotation of the injection device ensure the continuity of supplying liquid, but high speed will increase the threshold voltage, the best speed of metal rollers in this experiment is 5-10 r/min.In order to obtain honeycomb porous film, porous PVDF thin film was prepared by immersion precipitation method. The influence of concentration, molecular weight of PVP, content of additives, coating thickness, coagulation bath and other factors on the formation of the pore structure of PVDF film is analyzed. The best technology parameters are: The concentration of PVDF is 10%, the molecular weight of the PVP is 1300000, additive content is 10%, the coagulation bath is distilled water and ethanol water solution, of which volume ratio is 1:1. The membranes prepared were investigated by SEM, XRD, FT-IR and other physical characterization.The modified PVDF films were characterized by XRD, DSC, and electrochemical performance test. The experimental results show that the discharge platform is about 3.4 V, and that the specific capacity is 140 m Ah/g for both sides of modified membrane...