Gel electrolyte diaphragm, preparation method thereof and lithium ion battery

The invention belongs to the technical field of battery materials, and particularly relates to a gel electrolyte diaphragm, a preparation method thereof and a lithium ion battery. The gel electrolyte diaphragm comprises a high-molecular polymer material, lithium bis(trifluoromethanesulfonyl) imide and guanidine salt ionic liquid. The guanidine salt ionic liquid in the gel electrolyte diaphragm has the advantages of stability, no volatilization, long service life, high conductivity and the like, and nitrogen contains lone pair electrons which can be coordinated with metal ions and particularly have a strong attraction effect on Mn, so that Mn generated by disproportionation reaction of a lithium manganate material is extracted; and Mn is prevented from attaching to the negative electrode to cause capacity attenuation. The gel electrolyte diaphragm is a porous polymer diaphragm, is suitable for being used in a lithium manganate battery, and can effectively prevent Mn from migrating to a negative