Lithium-ion battery silicon oxide composite negative electrode material and preparation method thereof, lithium-ion battery

Abstract

The invention discloses a method for preparing a silicon oxide composite negative electrode material for a lithium-ion battery. The preparation method includes: disproportionating a silicon oxide raw material by high-temperature roasting to obtain a disproportionated silicon oxide raw material; the first stage: disproportionating the obtained silicon oxide The silicon raw material is roasted, heated to 500-1000°C for roasting under protective gas, kept for 0.5-2 hours, and the organic gas is introduced for 1-20 hours. After the reaction is complete, the organic gas is turned off; the second stage: continue to heat up to 1000-1800°C, feed hydrogen and organic gas, the ventilation time is 1-20h, after the reaction is complete, lower the temperature and cool down to obtain the silicon oxide composite negative electrode material; the obtained silicon oxide composite negative electrode material is crushed, sieved, Demagnetization obtains silicon oxide composite negative electrode material for lithium ion battery. The silicon oxide composite negative electrode material for the lithium ion battery prepared by the preparation method has good cycle performance and electrical conductivity, and prolongs the service life of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a lithium-ion battery silicon oxide composite negative electrode material, a preparation method thereof, and a lithium-ion battery. Background technique [0002] Compared with traditional batteries, lithium-ion secondary batteries are mainly manifested in many aspects such as large specific capacity, long cycle life, high safety, and less environmental pollution. At present, the anode materials of lithium-ion secondary batteries that have been commercialized are mainly carbon materials, and have been successfully applied to various electronic products, automobiles and other equipment. However, the main problem of carbon materials is that their maximum theoretical specific capacity is only 372mAh / g, which is difficult to meet the current demand. [0003] As a negative electrode material for lithium-ion batteries with great potential at present, silicon-based materia...

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Problems solved by technology

However, the main problem of carbon materials is that their maximum theoretical specific capacity is only 372mAh / g, which is difficult to meet the current demand

[0003] As a negative electrode material for lithium-ion batteries with great potential at present, silicon-based materials have the main advantage of large specific capacity. Among them, the theoretical specific capacity of silicon material reaches 4200 mAh / g, and the theoretical specific capacity of silicon oxide material also reaches 4200 mAh / g. 2100mAh / g, much larger than the carbon negative material, but the defect of silicon material is also obvious, mainly manifested in the cycle process, the expansion rate can reach more than 300%, and the conductivity of the silicon-based material is also very poor, resulting in its cycle During the process, the active material is easy to pulverize and fall off, which seriously affects the service life of the battery. Therefore, improving the cyclic expansion and conductivity of silicon-based materials is the current research focus and difficulty of silicon-based materials.

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