Preparation method of lithium ion battery silicon-carbon composite cathode material

Abstract

The invention discloses a preparation method of a lithium ion battery silicon-carbon composite cathode material. The preparation method is characterized by comprising the following steps: 1), dissolving ethyl orthosilicate in a mixed solution of absolute ethyl alcohol and deionized water, adding organic acid in the solution, regulating the pH value of the solution to 3-5, and marking the solution as a solution A; 2), adding graphite particles in the solution A, stirring the mixture, and marking the mixture as a mixture B; 3), slowly adding ammonia water in the mixture B while stirring by high speed magnetic force, wherein the concentration of the ammonia water is 10-20%, adding a basic catalyst until forming gel; 4), drying gel prepared in the step 3 at 90-110 DEG C; 5), introducing hydrocarbon gas and nitrogen or the mixed gas of nitrogen and argon to the gel material prepared in the step 4 at 600-800 DEG C for 2-6 h, and then introducing high-pure nitrogen or high-pure argon, raising the temperature to 900-1200 DEG C, keeping the temperature for 1-6 h, cooling the mixture, and at last obtaining the silicon-carbon composite cathode material.

Description

technical field [0001] The invention belongs to the field of electrochemical power sources, and relates to a method for preparing a silicon-carbon composite negative electrode material for a lithium ion battery, in particular to a method for preparing a silicon / graphite / amorphous carbon composite negative electrode material for a lithium ion battery. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high specific energy, wide operating temperature range, stable discharge, small size, light weight, and no memory effect. They have been shown in portable electronic equipment, electric vehicles, space technology, and defense industries. Broad application prospects III. With the increasing demand for high-capacity, long-life batteries for mobile electronic devices, people have put forward higher requirements for the performance of lithium-ion batteries. As an important factor to improve the energy and cycle life of lithium-ion batte...

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Problems solved by technology

However, the volume of silicon will change drastically during the charging and discharging process, resulting in unstable cycle performance of the motor, resulting in battery failure, and its high initial irreversible capacity limits its application as a negative electrode material for lithium-ion batteries.

[0005] At present, the most widely used method is to optimize and modify nano-silicon materials by doping and coating methods to make this material more stable and improve the cycle performance of batteries to a certain extent. However, the problem of easy agglomeration of nano-silicon materials still remains. can't solve

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