High-compaction silicon-carbon composite negative electrode material as well as preparation and application thereof

A technology of silicon-carbon composite materials and silicon-carbon composites, which is applied in the preparation/purification of carbon, silicon compounds, silicon oxide, etc., can solve the problems of difficult control of oxygen content, low compaction density of silicon-carbon composite materials, and weak interface bonding, etc. problems, to achieve the effect of improving the tap density, improving the electrochemical performance, and improving the interface binding effect

Active Publication Date: 2020-12-04
湖南宸宇富基新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the deficiencies of the prior art and improving the problems that the oxygen content in the silicon material is difficult to control, the compaction density of the silicon-carbon composite material is low, and the interface is not firmly bonded, the first purpose of the present invention is to provide a low-oxygen porous silicon-based Silicon-carbon composite negative electrode active materials, aiming to improve electrochemical performance such as cycle stability, first Coulombic efficiency, and rate performance

Method used

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  • High-compaction silicon-carbon composite negative electrode material as well as preparation and application thereof
  • High-compaction silicon-carbon composite negative electrode material as well as preparation and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0095] Using SiO coarse powder with an average particle size of 0.5 mm as raw material, after crushing and crushing, SiO fine powder with an average particle size of 1 μm is obtained; chemical vapor deposition method is used, acetylene is used as raw material gas, argon is used as carrier gas, and the deposition temperature is at 650°C, holding time 1h, gas flow rate of acetylene 120ml / min, argon 40ml / min, coating a thin carbon layer on the surface of SiO fine powder to obtain silicon monoxide particles (SiO@C) wrapped in a thin layer of carbon; SiO @C particles, metallic Mg, non-metallic B powder, mixed salt (LiCl:NaCl molar ratio 7:3, eutectic point 570°C) were mixed and granulated by extrusion granulation according to the mass ratio of 1:0.2:0.05:1 pellets to obtain a composite precursor; put the composite precursor into a sintering boat and place it in a muffle furnace for sintering reaction under an argon atmosphere, and heat up to 700°C at a speed of 5°C / min, react for 6 ...

Embodiment 2

[0100] Mix the low-oxygen porous silicon prepared in Example 1, artificial graphite powder with a particle size of 6 μm, pitch with a particle size of 3 μm, and toluene in a mass ratio of 1:0.5:0.08:4 and mix them uniformly in a high-speed disperser, then Spray granulation was performed to obtain a silicon-carbon precursor; the silicon-carbon precursor was placed in a cauldron and subjected to carbonization heat treatment at 950° C. for 2 hours under an argon atmosphere. After cooling, disperse with a jet mill to obtain a silicon-carbon intermediate with an average particle size of 13 μm; carry out particle size grading with artificial graphite with a particle size of 20 μm in a mass ratio of 1:1 to obtain the high-compact silicon-carbon composite negative electrode material .

[0101] The silicon carbon negative plate was assembled into a CR2032 lithium-ion button battery, and the electrochemical performance was tested in the voltage range of 0.01-2V at room temperature, and ...

Embodiment 3

[0103] Mix the low-oxygen porous silicon prepared in Example 1, artificial graphite powder with a particle size of 2 μm, phenolic resin with a particle size of 1 μm, and acetone at a mass ratio of 1:2:0.2:8 and mix them uniformly in a high-speed disperser. Then spray granulation was carried out to obtain the silicon-carbon precursor; the silicon-carbon precursor was placed in a cauldron and subjected to carbonization heat treatment at 800° C. for 4 hours under an argon atmosphere. After cooling, disperse with a jet mill to obtain a silicon-carbon intermediate with an average particle size of 8 μm; carry out particle size grading with artificial graphite with a particle size of 15 μm in a mass ratio of 1:1 to obtain the high-pressure compacted silicon-carbon composite negative electrode material .

[0104] The silicon carbon negative plate was assembled into a CR2032 lithium-ion button battery, and the electrochemical performance was tested in the voltage range of 0.01-2V at ro...

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Abstract

The invention belongs to the field of preparation of silicon-carbon negative electrode materials, and particularly discloses a silicon-carbon composite material based on low-oxygen-content porous silicon, which comprises silicon-carbon composite particles and a carbon component a, the silicon-carbon composite particles comprise amorphous carbon substrates, small-particle-size carbon particles b and low-oxygen-content porous silicon particles; the low-oxygen-content porous silicon particle comprises an inner core and a shell compounded on the surface of the inner core, wherein the inner core islocally non-crystallized silicon SiOy with a low oxygen-containing porous structure, and the shell is a thin carbon coating layer; 0 < y < 1; the thickness of the thin carbon coating layer is not more than 100nm the core and / or shell material is doped with a non-metallic element E; and the non-metallic element E is at least one of boron, nitrogen, phosphorus and sulfur. The invention also provides a preparation method of the material. Research finds that the material with the components and the morphological structure can show better reversible capacity, rate capability and cycling stability.

Description

technical field [0001] The invention belongs to the technical field of lithium battery electrode materials, and in particular relates to a high-pressure compacted silicon-carbon composite powder material based on low-oxygen porous silicon and a preparation method thereof. Background technique [0002] Due to its advantages of high theoretical capacity, good safety performance and wide range of sources, silicon is expected to replace graphite materials as the anode material for next-generation high-energy-density lithium-ion batteries. However, the huge volume expansion and low intrinsic conductivity of silicon during the charge-discharge process lead to poor cycle and rate performance of the battery. Silicon monoxide (SiO) can react with lithium ions during the first charge and discharge process to form electrochemically inert Li 2 O and Li 2 SiO 4 , effectively alleviate the volume expansion problem of the active material, and improve the cycle performance of the battery...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/05C01B33/021C01B33/113H01M4/48H01M4/62H01M10/0525
CPCC01B32/05C01B33/021C01B33/113H01M4/483H01M4/625H01M10/0525Y02E60/10
Inventor 周昊宸周向清王鹏周进辉
Owner 湖南宸宇富基新能源科技有限公司
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