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, which comprises the following steps: step (1), dissolving micromolecular silane and ethylenediamine in a conventional organic solvent according to a mass ratio of 0.5: 1 to 10: 1, and stirring at room temperature for 5-10 hours to obtain a yellow solution; (2) mixing the yellow solution in the step (1) with a Grignard reagent, stirring at room temperature for 2 hours, and purifying to obtain an organic group modified silicon cluster mixed solution; and (3) carrying out vacuum pumping on the mixed solution in the step (2) to obtain a yellow solid, putting the yellow solid into a tubular furnace, carrying out heat treatment on the yellow solid in a temperature range of 500-1000 DEG C under the protection of flowing high-purity argon, and cooling to obtain the sub-nano silicon-carbon composite material. The method disclosed by the invention has the advantages of mild reaction conditions and easiness in amplification and regulation, is expected to be used for industrially preparing the sub-nano silicon-carbon composite, and is applied to the field of energy sources, especially 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 subnano silicon-carbon composite material by a liquid phase method. Background technique [0002] Silicon-carbon composite materials have received great attention in the field of high-energy-density lithium-ion batteries due to their high energy density, relatively suitable working potential, and abundant reserves of silicon in the earth's crust. Silicon-carbon composite materials are generally considered to be the most promising alternatives to the current mainstream graphite anode, becoming 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 charging and discharging, which leads to shortened battery cycle life. Therefore, it is particularly important to use small-sized silicon materials (especial...

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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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