Negative pole piece, preparation method thereof and lithium ion battery

Abstract

The invention relates to the technical field of lithium ion batteries, and discloses a negative pole piece which comprises a negative current collector, and the surface roughness Ra of the negative current collector is less than or equal to 3.0 microns; the negative electrode coating comprises a negative electrode active substance and a binder, and the negative electrode active substance comprises deposited silicon carbon and graphite in a mass ratio range of (1: 19)-(1: 3); the binder is a water-based binder and comprises polyacrylic acid and polyethylene glycol in a mass ratio range of (1: 0.25)-(1: 1.5); at least one side surface of the negative electrode current collector is coated with the negative electrode coating, and a first coating, a second coating and a third coating are sequentially formed on the surface of the negative electrode current collector; wherein the porosity of the first coating is smaller than that of the second coating, and the porosity of the second coating is smaller than that of the third coating. Therefore, by optimizing the structures of the negative electrode current collector and the negative electrode coating, the adhesive force can be remarkably improved, so that the high-rate response and the super-long cycle stability of the negative electrode are improved. The invention further discloses a preparation method of the negative pole piece and a lithium ion battery.

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