Preparation method of silicon-carbon negative electrode material for lithium ion battery

A lithium-ion battery and negative electrode material technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of poor cycle stability of silicon carbon negative electrode materials, and achieve the effect of improving cycle performance and alleviating volume expansion.

Active Publication Date: 2015-04-22
TIANJIN B&M SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a preparation method of silicon-carbon negative electrode material for lithium ion battery, to solve the problem of poor cycle stability of silicon-carbon negative electrode material

Method used

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  • Preparation method of silicon-carbon negative electrode material for lithium ion battery
  • Preparation method of silicon-carbon negative electrode material for lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) High-energy ball milling step: performing mechanical high-energy ball milling on the mixture of Si, SiO and natural graphite to obtain a ball milling mixture. The ball-to-material ratio during ball milling was 10:1, the rotational speed was 300 rpm, and the ball milling time was 10 hours.

[0022] (2) Micro-oxidation step: place the ball-milled mixture in a porcelain ark with a charging thickness of 0.5 cm, put it into a tube furnace at 200 ° C, feed air at a flow rate of 0.1 L / min and keep warm for 0.5 h, take it out and place it in a dry box to cool naturally.

[0023] (3) Organic carbon coating step: mix asphalt and tetrahydrofuran in a weight ratio of 0.5:1 to obtain an organic carbon source solution, then add the ball mill mixture treated in the micro-oxidation step and mix for 2 hours, wherein the ball mill mixture The weight ratio with the organic carbon source solution is 1:2. The mixed solution was heated and evaporated to dryness at 100° C. to obtain a m...

Embodiment 2

[0026] (1) High-energy ball milling step: performing mechanical high-energy ball milling on the mixture of Si, natural graphite and artificial graphite to obtain a ball milling mixture. The ball-to-material ratio during ball milling was 5:1, the rotational speed was 500 rpm, and the ball milling time was 30 hours.

[0027] (2) Organic carbon coating step: mix the organic carbon source and the solvent at a weight ratio of 0.1:1 to prepare an organic carbon source solution, then add the ball mill mixture and mix for 0.5 h, wherein the organic carbon source is glucose and sucrose The mixture is formed, the solvent is a mixed solution composed of tetrahydrofuran and cyclohexane, and the weight ratio of the ball mill mixture to the organic carbon source solution is 1:3. The mixed solution was heated and evaporated to dryness at 200°C to obtain the precursor material;

[0028] (3) High-temperature carbonization step: the precursor material is placed in a tube furnace, and roasted u...

Embodiment 3

[0031] (1) High-energy ball milling step: performing mechanical high-energy ball milling on the mixture of Si, SiO and graphitized mesophase carbon pellets to obtain a ball milling mixture. The ball-to-material ratio during ball milling was 20:1, the rotational speed was 400 rpm, and the ball milling time was 20 hours.

[0032] (2) micro-oxidation step: the ball mill mixture is placed in a porcelain ark with a charging thickness of 1 cm, put into a tube furnace at 100 ° C, and O 3 And keep it warm for 2 hours, take it out and put it in a dry box to cool naturally.

[0033] (3) Organic carbon coating step: mix the organic carbon source and the solvent at a weight ratio of 0.05:1 to obtain an organic carbon source solution, then add ball mill mixture and mix for 4 hours, wherein the organic carbon source is pitch and phenolic resin And a mixture composed of epoxy resin, the solvent is a mixed solution composed of water, ethanol and isopropanol, and the weight ratio of the ball ...

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Abstract

The invention discloses a preparation method of a silicon carbon negative electrode material for a lithium ion battery. The preparation method comprises the following steps: high-energy ball milling, organic carbon coating, high-temperature carbonization and micro-oxidation, wherein the micro-oxidation step is carried out after the high-energy ball milling step and before the organic carbon coating step, and is carried out at least once after the high-temperature carbonization step. The previous and/or subsequent micro-oxidation treatment can ensure that a SiO2 layer is oxidized on the Si surface, and play a role of oxidation and pore-forming on graphite and pyrolytic carbon; a SiO2 electrochemical inert layer inhibits the volume expansion of Si to a certain extent, while the porous structure can relieve the volume expansion of Si to a certain extent, thereby improving the cyclic performance of the silicon carbon negative electrode material.

Description

Technical field: [0001] The invention relates to a lithium ion battery, in particular to a method for preparing a silicon carbon negative electrode material for a lithium ion battery. Background technique: [0002] At present, graphite-based carbon materials are still the main anode materials for lithium-ion batteries. Graphite-based carbon materials have high electronic conductivity, large diffusion coefficient of lithium ions, small volume change of layered structure before and after lithium intercalation, and good compatibility with electrolyte. Etc. However, due to the constraints of the structural properties of graphite itself, the development of graphite anode materials has also encountered a bottleneck. For example: the specific capacity is already close to the limit of the theoretical capacity of 372mAh / g, and it has gradually failed to meet the continuous high-current discharge capability required by large-scale power batteries. The alloy anode material represente...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62
CPCH01M4/386H01M4/48H01M4/587Y02E60/10
Inventor 徐宁高川梁运辉吴孟涛杨化滨
Owner TIANJIN B&M SCI & TECH
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