Preparation method of silicon carbon negative electrode precursor

Abstract

The invention discloses a preparation method of a silicon carbon negative electrode precursor. The preparation method comprises the steps of adding nanometer silicon powder and carbon micro powder into an organic solvent, and performing grinding and dispersion to form paste A; adding a nanometer carbon material into the organic solvent, and performing uniform dispersion to form paste B; adding a binding agent into the organic solvent, and performing uniform dispersion to form paste C; mixing and uniformly dispersing the paste A, the paste B and the paste C to form paste D; and performing spraydrying granulation on the paste D to obtain the silicon carbon negative electrode precursor. Multi-step dispersion is employed, the dispersion performance and the stability of the mixed paste are improved, the dispersion process time is reduced, the dispersion efficiency is improved, a relevant risk such as granulation plug is reduced, and subsequent application and mass production are facilitated; meanwhile, the carbon micro powder and the nanometer carbon material are introduced, on one hand, the problem of silicon conductivity is solved, the internal resistance is reduced, and the initialcoulombic efficiency and the rate performance are improved; and on the other hand, the volume expansion during the charge-discharge process of silicon is solved, the integral expansion rate of the material is reduced, the material pulverization is prevented, and the cycle property is improved.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a preparation method of a structurally stable silicon-carbon negative electrode precursor. Background technique [0002] Lithium-ion batteries have the characteristics of high working voltage, high energy density, light weight, and environmental friendliness, and are widely used in various portable electronic devices and electric vehicles. At present, the commercial lithium-ion battery anode materials are mainly graphite, but the low specific capacity (theoretical specific capacity is 372mAh / g) limits its further development in the energy density of lithium-ion batteries. As a representative of new high-capacity materials, silicon materials have the advantages of high lithium storage capacity (theoretical specific capacity 4200mAh / g), low discharge platform, and abundant reserves, which has become a breakthrough to solve the goal of 300Wh / kg. [0003] How...

AI Technical Summary

Problems solved by technology

This material has good electrical conductivity, but the composite structure and particle size controllability of the material are poor, which eventually leads to poor performance of the material capacity, only 450mAh / g, and the first effect is as low as 85%. This method is difficult to be commercialized in the future.

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