Lithium-ion battery silicon carbon negative electrode material and preparation method thereof

Abstract

The invention provides a lithium-ion battery silicon carbon negative electrode material and a preparation method thereof. The preparation method of the lithium-ion battery silicon carbon negative electrode material comprises the following steps: S1, after mixing a silicon source and a solvent, wet grinding is performed under an oxidizing condition to form an oxide layer on the surface of the silicon source, wherein the mass of oxygen element accounts for 9.8% to 14% of the mass of the silicon source, and a slurry is obtained; S2, the slurry obtained in step S1 is compounded with a carbon material and dried to obtain a silicon carbon core material; S3, the silicon carbon core material obtained in step S2 is subjected to a fusion process treatment, and then mixed with a carbon coating material uniformly, and then calcined at a high temperature to be shaped; and S4, the material obtained in step S3 is crushed and sieved to obtain the silicon carbon negative electrode material. According to the invention, controlled oxidation of nano-silicon is realized during the wet grinding process, so that an oxide layer is formed on the surface of the silicon source; and the presence of the oxidelayer avoids side reactions between the silicon source and the electrolyte, and reduces the phenomenon of electrochemical agglomeration during the cyclic process at the same time; therefore, the cyclestability of the silicon carbon negative electrode material is significantly increased.

Description

technical field [0001] The invention relates to the technical field of chemical power sources, in particular to a silicon-carbon negative electrode material for a lithium-ion battery and a preparation method thereof. Background technique [0002] The new lithium-ion secondary battery is one of the hot spots in the development of new energy fields. It has attracted much attention due to its unique advantages such as high specific energy, high working voltage, wide application temperature range, long cycle life, and no pollution. It is the current commercial secondary battery. The most widely used system in the secondary battery, it has achieved great success in the field of portable electronic devices, and its application range is still expanding, and has become one of the most important power sources for new energy vehicles. [0003] Industrialized lithium-ion power batteries mainly have problems such as low energy density and high cost, and the key to solving these problems...

AI Technical Summary

Problems solved by technology

At present, commercial lithium-ion batteries mostly use graphite-based carbon anodes, but their low specific capacity (theoretical capacity 372mAh / g), rate performance and possible safety issues can no longer meet the actual needs of high-performance power batteries.

Silicon is considered to be the anode material for the next generation of high-energy-density lithium-ion batteries due to its ultra-high gram capacity (4200mAh / g), environmental friendliness, and abundant reserves. Morphological changes, which in turn affect the cycle performance of electrode materials, resulting in poor cycle performance

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