A negative electrode slurry for lithium-ion batteries based on graphene-silicon dioxide composite airgel and preparation method thereof

Abstract

The invention relates to the field of lithium batteries, and provides a cathode slurry of a lithium ion battery based on graphene-silicon dioxide composite aerogel and a preparation method thereof. The cathode slurry is prepared from the following components in parts by weight: 95 to 97 parts of graphene-silicon dioxide composite aerogel, 0 to 2 parts of conductive agent, 0 to 1 part of dispersant, 0.5 to 2.5 parts of adhesive, 0 to 2 parts of thickener, and 140 to 160 parts of water. The cathode slurry has the advantages that by containing the graphene-silicon dioxide composite aerogel material, the specific surface area is large, and the flexibility is higher; after the cathode slurry is covered to the surface of an cathode plate and is cured, the surface of the obtained cathode plate ismore smooth, the roughness is low, the puncturing of a diaphragm is effectively prevented, and the service life of the battery is prolonged.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a graphene-silicon dioxide composite airgel-based negative electrode slurry for lithium ion batteries and a preparation method thereof. Background technique [0002] With the development of new energy sources, lithium-ion batteries have made great progress in various fields. The positive and negative electrode materials of lithium-ion batteries play a key role in improving the performance of lithium-ion batteries. For lithium-ion negative electrode materials, carbon materials were used at the earliest, and then silicon, titanium, and composite materials appeared. On the other hand, graphene has a single-layer two-dimensional sheet structure, a large specific surface area, excellent electrical conductivity, thermal conductivity, low resistivity, etc., and is very suitable as a negative electrode material. The negative electrode sheet of many lithium-ion batteries in the prior art...

AI Technical Summary

Problems solved by technology

[0003] Although graphene has many advantages, after research, the inventors have found that graphene also has some disadvantages: although graphene has a single-layer two-dimensional sheet structure, the sheets between adjacent graphenes in actual use The spacing will gradually shrink, making the graphene less exfoliated, resulting in less flexibility and higher hardness

When graphene is used as the negative electrode material and coated on the surface of the negative electrode current collector (usually copper foil) and solidified, the hard graphene and other negative electrode particle materials will make the surface of the negative electrode sheet very rough. After working for a long time, due to the long-term extrusion contact between the battery separator and the negative electrode sheet and the influence of high temperature, the separator is easily pierced by the negative electrode sheet, and micro-short circuit or even diaphragm failure is prone to occur

[0004] Usually, in order to improve the puncture resistance strength of the diaphragm in the prior art, a layer of ceramic coating will be coated on the surface of the diaphragm, but this will bring new problems: due to the setting of the ceramic coating, the gas permeability of the diaphragm and the impact on the The wettability of the electrolyte is greatly reduced, which affects battery performance

[0006] Although the above-mentioned patent uses graphene-loaded negative electrode particles (carbon, silicon materials), it is similar to the technical solution of the present invention on the surface, but it only uses graphene to coat the negative electrode material to solve the problem of easy expansion of carbon and silicon negative electrode materials. The technical problem of the failure of the negative electrode material cannot solve the technical problem of the rough surface of the negative electrode sheet made of graphene and other negative electrode materials