Negative electrode slurry for making negative electrode of lithium ion battery and preparation method thereof, negative electrode of lithium ion battery and battery

Abstract

The invention discloses a negative electrode sizing agent for manufacturing a lithium ion battery negative electrode, a preparation method of the negative electrode sizing agent, the lithium ion battery negative electrode and a battery. The negative electrode sizing agent is mainly prepared from active materials, a conductive agent, a binding agent and a solvent. The active materials are prepared from, by weight, 5-10% of nanometer silicon powder and 90-95% of graphite powder, wherein the nanometer silicon powder is spherical, and the grin size in the BET of the nanometer silicon powder is not larger than 80 nm; the solvent is prepared from, by weight, 0-50% of water and 50-100% of a volatile organic solvent, wherein the volatile organic solvent is absolute ethyl alcohol or propyl alcohol or butanone. The negative electrode sizing agent can effectively solve the problem that nanometer silicon powder cannot be well dispersed in the sizing agent, the volatile organic solvent is adopted for preparing the sizing agent, reagglomeration and segregation of the dispersed nanometer silicon powder can be effectively reduced, and uniform distribution of nanometer silicon powder particles in a particle dispersion mode is ensured.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a negative electrode slurry for making a lithium ion battery negative electrode, a preparation method thereof, a lithium ion battery negative electrode and a battery. Background technique [0002] With the development of mobile portable electronic products and new energy electric vehicle technology, higher and higher requirements are put forward for the development of long-range energy lithium-ion batteries. [0003] The theoretical lithium storage capacity of silicon has reached 4200mAh / g, which is more than 10 times the capacity of graphite material (theoretical capacity is 372mAh / g), and the voltage platform of silicon is slightly higher than that of graphite, so it is difficult to cause lithium precipitation on the surface during charging, and the safety performance is better , the earth is rich in silicon, and silicon has become one of the potential choices for the upgrading of carbo...

AI Technical Summary

Problems solved by technology

The use of nano-silica powder can effectively relieve the volume expansion of silicon-based negative electrode materials. However, due to the large difference in specific gravity between nano-silica powder and graphite powder, when the two are combined as active materials, after slurrying according to existing conventional methods, the During the drying process of coating and film formation, due to the difference in specific gravity between the two, it is very easy to cause floating slurry and agglomeration of nano silicon powder, which will affect the overall performance of lithium-ion batteries. In this way, not only the effective capacity of nano silicon powder cannot be exerted, but also Will reduce the cycle life of the battery

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