Cellulose-composite polyethylene diaphragm for lithium ion battery and preparation method thereof

Abstract

The invention relates to the technical field of a lithium ion battery diaphragm technology and discloses a cellulose-composite polyethylene diaphragm for a lithium ion battery and a preparation method thereof. The diaphragm comprises a diaphragm base and a coating. The diaphragm base is prepared from 65-75 parts by weight of polyethylene, 5-10 parts by weight of vinyl acrylate, 5-10 parts by weight of natural cellulose slurry, 3-5 parts by weight of keratin, 1-3 parts by weight of ethylene glycol diglycidyl ether and 8-10 parts by weight of brown algae extract. The coating is prepared by coating the surface of the diaphragm base with coating slurry and is prepared from 1-5 parts by weight of a nanometer inorganic filler, 3-5 parts by weight of a binder, 20-30 parts by weight of vinyl acrylate, 1-5 parts by weight of mussel shell powder, 1-5 parts by weight of halloysite nanotubes and 57-67 parts by weight of an organic solvent. The cellulose-composite polyethylene diaphragm can resist a high temperature, keeps size stability after heating, has good moisture absorption and retention capability and good wellability with electrolyte, and has good stabbing strength.

Description

technical field [0001] The invention relates to the technical field of preparation of lithium-ion battery separators, in particular to a polyethylene separator compounded with cellulose for lithium-ion batteries and a preparation method thereof. Background technique [0002] The diaphragm is a very important part of the lithium-ion battery. The main function of the diaphragm is to separate the positive and negative electrodes of the battery and prevent the short circuit caused by the contact between the positive and negative electrodes. The separator itself is a non-conductive material with certain micropores and porosity, allowing electrolyte ions to pass through. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle performance, and safety performance of the battery. In the prior art, most lithium-ion batteries use polyolefin porous membranes as their diaphragm materials. [...

AI Technical Summary

Problems solved by technology

But on the other hand, the setting of the ceramic slurry blocks the micropores on the original diaphragm to a certain extent, and reduces the wettability and gas permeability of the diaphragm to a certain extent. In addition, the ceramic slurry is generally bonded by an adhesive. Attached to the base film of the diaphragm, the adhesive force is not strong enough, and it is easy to fall off after a long time