Lithium ion battery positive 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 positive electrode sheet containing an electric-conduction coating, and a preparation method thereof. The positive electrode sheet comprises an aluminum foil current collector, an electric-conduction coating and a positive electrode active material layer, wherein the positive electrode active material layer is formed by curing a positive electrode slurry, the positive electrode slurry comprises 91-95 parts of lithium iron phosphate, 1-3 parts of electric-conduction carbon black SP, 0.5-1.5 parts of vapor grown carbon fiber, 3-5 parts of polyvinylidene fluoride, and 60-80 parts of N-N-dimethylpyrrolidone, the electric-conduction coating is formed by curing an electric-conduction slurry, and the electric-conduction slurry 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 canbe improved.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a lithium ion battery positive electrode sheet containing a conductive coating and a preparation method thereof. Background technique [0002] At present, the positive electrode sheet of the lithium ion battery generally includes a current collector and a positive electrode active material coated on the current collector. Among them, the current collector of the positive electrode mainly adopts aluminum foil and light foil. Due to the smooth surface of the light foil, the interface binding force between the positive electrode active material and the current collector is weak when coating, resulting in poor adhesion of the positive electrode active material, which is prone to 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 binder needs t...

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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