Ferrosilicon composite negative electrode material and preparation method thereof

Abstract

The invention provides a silicon iron composite negative electrode material and a preparation method thereof. The preparation method of the ferrosilicon composite negative electrode material comprises the following steps: adding ferrosilicon alloy into a solvent, and grinding and mixing to obtain ferrosilicon alloy slurry; adding the conductive agent slurry and a carbon source into the ferrosilicon alloy slurry, and dispersing and stirring to obtain nano mixed slurry; carrying out spray drying operation on the nano mixed slurry to obtain a spherical particle precursor; adding the carbon-coated material into the spherical particle precursor, and stirring and mixing to obtain a carbon-coated ferrosilicon alloy; and carrying out carbonization operation on the carbon-coated ferrosilicon alloy to obtain the ferrosilicon composite negative electrode material. According to the preparation method of the silicon iron composite negative electrode material, the specific capacity and the first charge-discharge efficiency of the silicon iron composite negative electrode material can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of new materials, in particular to a silicon-iron composite negative electrode material and a preparation method thereof. Background technique [0002] As lithium-ion batteries become more widely used, the requirements for comparing energy and cost are getting higher and higher. At present, graphite anode materials are mainly used in commercialization. After nearly 30 years of development, its energy density is close to the theoretical level (theoretical specific capacity is 372mAh / g), which limits the further improvement of lithium-ion battery energy density. In recent years, high-capacity anode materials have received extensive attention, among which silicon anode materials have good development prospects due to their high specific capacity (theoretical specific capacity reaches 4200mAh / g). [0003] However, due to the large volume expansion of the silicon anode during the charging and discharging process...

AI Technical Summary

Problems solved by technology

[0003] However, the cycle performance of the silicon negative electrode is poor due to the large volume expansion during the charging and discharging process. At present, the silicon-carbon negative electrode material is mainly prepared by nanonization and carbon coating and composited with graphite, and has been applied industrially. However, the cost of nanonization of silicon High, the amount of silicon added is currently low

Ferrosilicon alloy can reduce volume expansion during charge and discharge, but due to poor conductivity, the effective specific capacity is low

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