Lithium ion battery negative electrode slurry as well as preparation method and application thereof

Abstract

The invention relates to lithium ion battery negative electrode slurry as well as a preparation method and application thereof. According to the lithium ion battery negative electrode slurry, a specific raw material ratio is adopted, any one or a combination of at least two of N-methyl pyrrolidone, N, N-dimethylformamide and acetamide is adopted as a solvent, and oxalic acid and / or citric acid is / are adopted as an additive; the moisture content of a negative pole piece prepared from the slurry is extremely low; after a battery is assembled, the internal moisture content of the battery is reduced, so that the decomposition of LiPF6 in electrolyte is reduced; meanwhile, by adopting the negative electrode slurry disclosed by the invention, the bonding strength between a negative electrode active substance and a copper foil can be improved, so that the electrical property of the lithium ion battery after high-temperature storage is improved; and the preparation process of the lithium ion battery negative electrode slurry has a large preparation process window, and hard carbon, graphite, lithium titanate or soft carbon can be adopted as a negative electrode active substance.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a lithium ion battery negative electrode slurry, a preparation method and application thereof. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products, electric vehicles and other fields due to their high operating voltage, wide operating temperature range and environmental friendliness. With the development of technology, in order to meet some special use environments, such as military industry or extreme high temperature environment, the battery will be required to withstand the high temperature environment or cycle of 80 ~ 100 ℃, which requires the battery to have higher high temperature resistance storage capacity and high temperature resistance cycle capacity. [0003] When lithium-ion batteries are stored at high temperatures, the presence of moisture will accelerate LiPF 6 The decomposition of lithium-ion batteries degrades the high-t...

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Problems solved by technology

[0004] CN107834023A discloses a water-based negative electrode slurry. By adding low-polarity ethylene carbonate, the dispersibility of the negative electrode active material and the conductive agent in deionized water is effectively adjusted, so that the components of the slurry are evenly dispersed, reducing particle agglomeration or even There is no particle agglomeration phenomenon, but this method is very limited to reduce the surface tension of the solvent, and is sensitive to the dispersion process, and it is too strong for the special type of negative electrode material, so it is not a common application method

[0005] CN106169559A discloses a preparation method of low-temperature, high-magnification negative electrode slurry, which adopts hard carbon and artificial graphite as main materials, first prepares N-methylpyrrolidone solution of polyvinylidene fluoride, and then adds conductive agent, hard carbon, Graphite and oxalic acid, polyvinylidene fluoride in the negative electrode slurry prepared by this method cannot be fully mixed in the active material particles, and the bonding performance is insufficient

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