Silicon-carbon negative electrode material, preparation method and application

A negative electrode material, silicon carbon technology, applied in the field of energy storage electrode materials, can solve the problems of high preparation cost of ultrafine nano silicon, poor process controllability, volume expansion, etc., and achieves favorable rate and cycle performance, excellent cycle performance, The effect of reducing the expansion rate

Pending Publication Date: 2021-11-16
四川金汇能新材料股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is that the volume expansion of silicon used in the negative electrode material of lithium-ion batteries will occur in the electrochemical reaction, and the preparation cost of ultra-fine nano-silicon used in the negative electrode materials of lithium-ion batteries High, poor process controllability, high pollution, etc., the purpose is to provide a silicon carbon negative electrode material, preparation method, application, to solve the above problems

Method used

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  • Silicon-carbon negative electrode material, preparation method and application
  • Silicon-carbon negative electrode material, preparation method and application
  • Silicon-carbon negative electrode material, preparation method and application

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Embodiment 1

[0062] A silicon-carbon negative electrode material, the composite material is a core-shell structure, and the core-shell structure is sequentially composed of a silicon core, a cavity layer, a lithium silicate layer, and a carbon layer from the inside to the outside, and the silicon core is a micron silicon , micropores are distributed on the lithium silicate layer, and the carbon layer covers the lithium silicate layer.

[0063] Specifically, the core-shell structure uses micro-silicon as the core, and the outer layer of the micro-silicon core is a cavity layer with a certain thickness. The cavity layer is a spherical cavity, and the outside of the cavity layer is a lithium silicate layer. The silicate layer is non-coated to the cavity layer, and there are micropores distributed on the lithium silicate layer. The micropores penetrate the lithium silicate layer and communicate with the cavity layer. Covered with carbon layer.

[0064] The thickness of the cavity layer is 60n...

Embodiment 2

[0068] A lithium-ion battery includes a silicon-carbon negative electrode material provided by an embodiment of the present invention.

Embodiment 3

[0070] A preparation method of silicon carbon negative electrode material, according to the following steps:

[0071] (1) Oxidation:

[0072] Take by weighing D50 (median particle size) be 0.8um, Dmax be 3kg of micron silicon powder body of 2.0um, add rotary kiln, the filling rate of rotary kiln is 21.6%, rotating speed 0.5r / min, compressed air flow 3L / min, with 5°C / min to 550°C for oxidation treatment for 60 minutes, the surface of the micron silicon powder is oxidized to form a silicon dioxide layer, and then it is naturally cooled to room temperature and taken out.

[0073] (2) Heat treatment:

[0074] After the oxidized micro-silicon powder is sieved with 270 mesh, it is uniformly mixed with lithium hydroxide powder at a molar ratio of 4.0, and then added to the rotary furnace. The rotating speed of the rotary furnace is 0.5r / min, and the rotary furnace Inert gas, heat treatment at 5°C / min to 500°C for 4 hours under an inert atmosphere; then stop heating and cool to room...

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Abstract

The invention discloses a silicon-carbon negative electrode material. The composite material is of a core-shell structure, and the core-shell structure sequentially comprises a silicon core, a cavity layer, a lithium silicate layer and a carbon layer from inside to outside; the silicon core is micron silicon, micropores are distributed in the lithium silicate layer, and the carbon layer coats the lithium silicate layer. The micron silicon is wide in source, low in cost, high in controllability of the preparation process and suitable for large-scale production, the hollow layer and the micropore structure provide a space for volume expansion and shrinkage in the charging and discharging process, the expansion rate of the powder is greatly reduced, structural collapse is avoided, the structure is stable, the reversible capacity is high, and the cycle performance is good. The material has a wide application prospect as a negative electrode material of a lithium ion battery. Through oxidation, heat treatment, etching and carbon coating, the preparation method is simple and feasible in process, free of pollution, simple in equipment, small in investment and suitable for large-scale production.

Description

technical field [0001] The invention relates to the technical field of energy storage electrode materials, in particular to a silicon-carbon negative electrode material, a preparation method and an application. Background technique [0002] Compared with traditional graphite anodes, silicon has an ultra-high theoretical specific capacity (4200mAh / g) and a lower delithiation potential (<0.5V). Silicon has become one of the potential choices for upgrading carbon-based anodes in lithium-ion batteries. . Based on the current demand for high-energy-density batteries for portable electronic consumer products and pure electric vehicles, silicon materials with high capacity have received extensive attention. However, silicon also has disadvantages as an anode material for lithium-ion batteries. Silicon is a semiconductor material with low electrical conductivity. During the electrochemical cycle, the intercalation and extraction of lithium ions will cause the volume of the mat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/62H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 吴云胜胡晓东吴泽轶何晓云石九菊郭泽都秦冯祥蒋勇明吴亚平
Owner 四川金汇能新材料股份有限公司
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