Lithium ion battery negative electrode sheet containing electric-conduction coating, and preparation method thereof

Abstract

The invention relates to the field of lithium batteries, and discloses a lithium ion battery negative electrode sheet containing an electric-conduction coating, and a preparation method thereof. The negative electrode sheet comprises a copper foil current collector, an electric-conduction coating and a negative electrode active material layer, wherein the negative electrode active material layer is formed by curing a negative electrode slurry, the negative electrode slurry comprises 93-95 parts of graphite, 1.5-2.5 parts of electric-conduction carbon black SP, 1-2 parts of sodium carboxymethylcellulose, 2-3 parts of styrene-butadiene rubber, and 130-150 parts of deionized water, the electric-conduction coating is formed by curing an electric-conduction slurry, and the electric-conductionslurry comprises 10-95 parts of a composite carbon source, 5-50 parts of a binder, 5-40 parts of a dispersing agent, and 450-550 parts of an organic solvent. According to the present invention, the current collector is coated with the special electric-conduction slurry layer, such that the specific surface area is large, the impedance is low, the bonding force of the electrode sheet can be substantially improved, the electric conductivity can be enhanced, the adding amounts of the binder and the electric-conduction agent can be reduced, and the energy density of the battery can be improved.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a lithium ion battery negative electrode sheet containing a conductive coating and a preparation method thereof. Background technique [0002] At present, the negative electrode sheet of the lithium ion battery generally includes a current collector and a negative electrode active material coated on the current collector. Among them, the current collector of the negative electrode mainly adopts copper foil and light foil. Due to the smooth surface of the light foil, the interface binding force between the negative electrode active material and the current collector is weak when it is coated, resulting in poor adhesion of the negative electrode active material, and it is easy to cause problems such as electrode sheet dropout in the later process. Therefore, the addition amount of the conductive agent must not be increased, and in order to ensure the electrode adhesion, more binde...

AI Technical Summary

Problems solved by technology

However, there are also some problems in the above-mentioned conductive coating: 1. Due to the addition of a layer of conductive coating, and the specific surface area of ​​the material in the conductive coating is not large enough, the impedance of the pole piece is increased; 2. Its adhesion to the current collector Still need to be further improved