Method for preparing silicon negative electrode material coated with vapor-deposited carbon nanotubes

Abstract

The invention discloses a method for preparing a silicon negative electrode material coated with vapor-deposited carbon nanotubes, which comprises the following steps in sequence: putting silicon powder and catalyst into a mixer and mixing them, taking them out; putting the mixed powder into In the fluidized bed, H 2 Reduce the powder; continue to reduce the obtained powder with N in the fluidized bed 2 Fluidize, feed carbon source gas, and react at a furnace temperature of 500~1000°C to obtain the product A after the reaction; the product A after the reaction is pulverized by airflow to obtain the finished product. The preparation method in the invention is simple and the cost is low; the prepared material enhances the conductivity of the electrode, limits the expansion and contraction during the process of silicon deintercalating lithium, and is suitable for negative electrodes of all lithium ion batteries.

Description

technical field [0001] The invention belongs to the field of battery materials, and relates to a preparation method of a negative electrode material of a lithium ion battery, in particular to a preparation method of a silicon negative electrode material coated with vapor-phase deposited carbon nanotubes. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, small self-discharge, wide operating voltage range, no memory effect, long service life, and no environmental pollution. They have been widely used in electronic products, electric vehicles, and energy storage fields. At present, the application of negative electrode materials is mainly based on traditional graphite materials, but the specific capacity of graphite is close to the theoretical value of 372mAh / g, and there is little room for improvement, which limits the energy density of lithium-ion batteries. Silicon-carbon composite materials have become the development trend of l...

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Problems solved by technology

[0003] However, silicon also has obvious disadvantages as the negative electrode material of lithium-ion batteries: firstly, as a semiconductor material, silicon itself has low electrical conductivity; secondly, in the process of charging and discharging, with the intercalation and extraction of lithium ions, the volume of silicon material changes greatly, resulting in material Pulverization and shedding will eventually lead to detachment from the current collector and poor cycle stability; finally, although methods such as doping and nanonization can be used to improve the electrochemical performance of silicon-based materials, these preparation methods are relatively complicated and costly , it is not easy to be prepared on a large scale, and the electrochemical performance of the prepared material needs to be further improved

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