Method for preparing sub-nano silicon carbon composite material by liquid phase method

Abstract

The invention discloses a method for preparing a sub-nano silicon carbon composite material by a liquid phase method, comprising the following steps: step (1), dissolving small molecular silane and ethylenediamine in a conventional In an organic solvent, stir at room temperature for 5-10 hours to obtain a yellow solution; step (2), mix the yellow solution in step (1) with Grignard reagent, stir at room temperature for 2 hours, and purify to obtain a silicon group modified by an organic group Cluster mixed solution; in step (3), the mixed solution in step (2) is decompressed and drained to obtain a yellow solid, and placed in a tube furnace, under the protection of flowing high-purity argon, in a temperature range of 500-1000 ° C The yellow solid is heat-treated, and the sub-nanometer silicon-carbon composite material is prepared after cooling. The method of the invention has the advantages of mild reaction conditions, easy amplification and regulation, is expected to be used for industrialized preparation of sub-nanometer silicon-carbon composites, and can be applied in the energy field, especially in the field of lithium ion batteries.

Description

technical field [0001] The invention belongs to the technical field of functional materials, in particular to a method for preparing a sub-nano silicon carbon composite material by a liquid phase method. Background technique [0002] Silicon-carbon composites have attracted great attention in the field of high-energy-density lithium-ion batteries due to their high energy density, relatively suitable working potential, and abundant silicon reserves in the earth's crust. Silicon carbon composites are generally considered to be the most promising alternative to the current mainstream graphite anodes and become a new generation of anode materials with high energy density. In the field of lithium-ion batteries, the biggest obstacle to the application of silicon carbon anodes is the huge volume change during the charging and discharging process, which leads to the shortening of battery cycle life. Therefore, it is particularly important to use small-sized silicon materials (especi...

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Problems solved by technology

The current mainstream process for the preparation of small-sized silicon materials is to use CVD or PVD methods to grow and deposit in high-temperature furnaces. This method can ensure continuous production, but the disadvantages are that it consumes a lot of energy and is harmful to the growth and deposition of silane gas. Silicon-forming particles cannot be precisely regulated, especially difficult to achieve the preparation of sub-nano-sized silicon materials

The newspaper Nature Energy, 2021, doi: 10.1038 / s41560-021-00945-z and the patent number CN201710527122.X announced a method for rapidly preparing sub-nanometer spherical silicon powder by arc, but these methods are still cumbersome and difficult to obtain sub-nanometer Dimensions of Silicon Carbon Composites

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