Modification method of silicon negative electrode material for lithium ion battery

Abstract

The invention relates to a modification method of a silicon negative electrode material of a lithium ion battery, which is characterized by comprising the following steps: by taking nano silicon powder and tetrabutyl titanate as raw materials, reacting under a hydrothermal condition, filtering and drying to obtain a precursor; and uniformly mixing the precursor and a carbon / nitrogen source according to a certain ratio, and carrying out heat treatment to obtain the two-layer coated silicon negative electrode lithium ion battery material which takes silicon nanoparticles as a core, takes a titanium nitride layer as a middle layer and takes a carbon layer as an outermost layer. The preparation method provided by the invention is simple and effective, and the prepared silicon-based negative electrode material has a carbon layer with good conductivity and a titanium nitride layer with a stable structure in a lithium ion deintercalation process, so that volume expansion of silicon in a charging and discharging process can be effectively slowed down. The core is elemental silicon with high specific capacity. Therefore, the material has good lithium storage performance.

Description

technical field [0001] The invention relates to a method for modifying a negative electrode material of a lithium ion battery, in particular to a method for modifying a silicon-based negative electrode material for a lithium ion battery. [0002] technical background [0003] Lithium-ion batteries are widely used due to their advantages such as large specific energy, long cycle life, stable discharge voltage, wide operating temperature range, low self-discharge rate and no memory effect. [0004] In recent years, people have been looking for ways to increase the specific energy of lithium-ion batteries. Silicon has attracted attention due to its high theoretical specific capacity. Compared with traditional graphite negative electrodes, silicon negative electrodes have obvious advantages in specific capacity; silicon is the second most abundant element in the earth's crust, and its abundant reserves make it a sufficient source of raw materials. However, the silicon negative e...

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Problems solved by technology

Silicon has attracted attention due to its high theoretical specific capacity. Compared with traditional graphite negative electrodes, silicon negative electrodes have obvious advantages in specific capacity; silicon is the second most abundant element in the earth's crust, and its abundant reserves make it a sufficient source of raw materials. However, the silicon negative electrode material will produce a large volume change during the process of lithium ion insertion and extraction, which will cause the pulverization of the silicon material and affect the cycle performance.

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