Preparation And Properties Of SiO₂/PEI Based Electrospun Fiber Battery Separators

Lithium-ion batteries have the advantages of no memory effect,high energy density,high working voltage,long service life,environmental protection and pollution-free,and become the main power source for all kinds of electronic products.The gradual popularization of new energy vehicles has provided a broad space for the development of lithium-ion batteries,and at the same time it has put forward higher requirements.The diaphragm has become a bottleneck restricting its rapid development.As one of the most convenient methods for preparing nanofibers,electrospinning has been extensively studied.The nanofiber film prepared by this method has the advantages of large specific surface area,high porosity,and small pore size,due to the availability of raw materials.Larger,and has the advantage of large liquid absorption rate,the application of electrospun film on lithium ion battery separator has been extensively studied.In this paper,polyetherimide(PEI)nanofiber membranes were prepared by electrospinning and modified on the basis of the original membranes.A layer of SiO2 inorganic shell was prepared on the surface of PEI fibers by in situ formation.In this paper,the scanning electron microscope,Fourier infrared light image,dynamic contact angle test,cycle life,rate performance and ionic conductivity,electrochemical window,etc.,the microstructure,structure,element composition electrolyte pro And properties,battery performance,and electrochemical performance were characterized.The results show that the PEI-SiO2 film exhibits excellent electrolyte affinity compared to the untreated pure PEI film and the commercial separator.It takes only 0.5 s to inhale the electrolyte,and has excellent heat resistance and heat shrinkage at 200?.The rate is 0%,the electrochemical window reaches 5.5 V,the capacity retention rate is as high as 98.6%after 50 cycles,and the capacity retention rate is as high as 79.2%at 8C discharge rate.In this paper,a layer of polymethyl acrylate(PMMA)was coated on the surface of SiO2 microspheres by emulsion polymerization.The prepared microspheres were subjected to scanning electron microscopy,transmission electron microscopy,and hydrophilic angle test.The average diameter of the SiO2 microspheres was 0.16 ?m,the average diameter of the PMMA@SiO2 microspheres was 0.31 ?m,and the thickness of the shell layer was 75 nm.The microspheres were coated on the surface of the PEI film to investigate the change of film properties before and after coating.The composite film with the same excellent performance was prepared.The equilibrium liquid absorption rate was as high as 741.4%,and the electrolyte was completely inhaled for 1.3 s.