Silicon carbon composite material, and preparation method and application thereof

Abstract

The invention discloses a silicon carbon composite material, and a preparation method and an application thereof. The preparation method comprises the following steps of performing wet process ball milling on glass powder and a laminated layer carbon material to obtain a uniform mixed product of glass and the carbon material; next, performing uniform mixing and compacting on the product and magnesium powder and fused salt to form an ingot; and then performing a magnesium thermal reaction, and carrying out acid washing on the reaction product to obtain a sandwich layer-shaped porous silicon/graphene-like structured composite material. The preparation method are simple in steps and easy to implement, and the raw materials are wide in resource; more importantly, the mixture is made into the ingot through the compacting process, and then the magnesium thermal reaction is performed, so that the tap density of the silicon carbon negative electrode material is greatly improved, and the volumetric specific capacity of the negative electrode material is improved; meanwhile, by compounding with the graphite and other carbon material to form the sandwich-like structure, the electronic conductivity of the material is improved effectively, and the compatibility between the silicon base material and an electrolyte can be improved, thereby improving cycle performance and rate capability of the material; and therefore, the silicon carbon composite material can be applied to the negative electrode material with high power density and high energy density of the lithium ion battery.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery negative electrode materials, and more specifically relates to a silicon-carbon composite material, its preparation method and application. Background technique [0002] Lithium-ion batteries have become an important energy storage device for portable electronic devices due to their high energy density. However, compared with traditional batteries, new batteries used in emerging electric transportation systems should have higher specific capacity, energy density and Better cycle life. Among the numerous anode materials for lithium-ion batteries, silicon is considered the most promising material due to its exceptionally high specific capacity, abundant reserves in the earth's crust, and well-developed manufacturing infrastructure. Silicon has been used in lithium-ion batteries for more than 30 years, but the mechanical crushing and rapid capacity decay of silicon materials seriously affect its c...

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Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a silicon-carbon composite material, its preparation method and application, the purpose of which is to uniformly mix waste silicate-based glass powder with sheet carbon material, After mixing with magnesium powder and molten salt, it is hydraulically formed into an ingot for magnesium thermal reaction to obtain a silicon-carbon composite material. The preparation method is simple, the process is safe, and the cost is low, and the prepared silicon-carbon composite material has a high tap density and compaction. Density, as a negative electrode material for lithium-ion batteries has good performance, thereby solving the problems of harsh preparation conditions, high cost, complicated steps, and serious pollution of the existing silicon-carbon negative electrode materials in the prior art, and the volume energy density of the silicon-carbon negative electrode material prepared at the same time and low power energy density, can not meet the application requirements of battery anode materials and other technical problems

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