Cathode active material for lithium ion battery, method for preparing cathode active material and cathode and battery with cathode active material

A negative electrode active material, lithium ion battery technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, secondary batteries, etc., can solve the problems of cracking and falling off of the outer layer silicon carbon material, avoid cracking and pulverization, avoid Contact surface cracking and peeling, the effect of alleviating volume expansion

Active Publication Date: 2017-09-26
BYD CO LTD
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

[0007] The present invention solves the problem of cracking and shedding of the outer silicon-carbon material caused by the uneven expansion of the inner layer graphite particles and the outer layer silicon-carbon composite particle composite material in the lithium-ion battery in the prior art, and maintains a good battery life. Electrical contact, improve battery cycle performance; provide a lithium-ion battery negative electrode active material, including graphite particles, and silicon-carbon composite particles dispersed on the surface of the graphite particles, the exposed surface area of ​​the graphite particles is 80% of the total surface area of ​​the graphite particles ~98%

Method used

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  • Cathode active material for lithium ion battery, method for preparing cathode active material and cathode and battery with cathode active material
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  • Cathode active material for lithium ion battery, method for preparing cathode active material and cathode and battery with cathode active material

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preparation example Construction

[0044] The present invention provides a lithium ion battery negative electrode, the negative electrode includes a negative electrode current collector and a negative electrode active material, the negative electrode active material includes a negative electrode active material, a negative electrode binder, and the negative electrode active material can also optionally include a negative electrode conductive agent, The negative electrode conductive agent is a conventional negative electrode conductive agent in the field; the preparation method of the negative electrode is a conventional lithium ion battery negative electrode preparation method in the field, including the negative electrode slurry obtained by mixing the negative electrode active material, the negative electrode binder, etc. with an organic solvent material coating and drying on the negative electrode current collector, the negative electrode current collector is a negative electrode current collector conventionall...

Embodiment 1

[0049] Step 1. Select nano-silicon with a particle size of 30nm and asphalt for ball milling (the ball milling process was carried out under a nitrogen atmosphere in the experiment, and no special instructions will be made later) to disperse. The mass ratio of nano-silicon and asphalt is 1:4, and the ball milling time is 2h , ball milling speed 250r / min. Under a nitrogen atmosphere, the temperature was raised at 5°C / min, and calcined at 500°C for 4h. After 210r / min, 1h ball milling. The particle size of the obtained silicon-carbon composite particles is 0.1 μm, which is marked as A1.

[0050] Step 2. Heat the asphalt to 100°C to turn the asphalt into a liquid state, add A1, the mass ratio of A1 to asphalt is 1:3, knead and stir at 100°C for 1 hour. After it is taken out and cooled, it is crushed by a pulverizer and marked as B1.

[0051] Step 3. Use a high-speed mixer at 300r / min to mix B1 and natural graphite particles with a particle size of 20um, and the ratio of B1 to g...

Embodiment 2

[0054] Step 1. Select nano-silicon with a particle size of 30nm and asphalt for ball milling (the ball milling process in the experiment was carried out under a nitrogen atmosphere, and no special instructions will be made in the follow-up). The mass ratio of nano-silicon and asphalt is 1:2, and the ball milling time is 2h , ball milling speed 250r / min. Under a nitrogen atmosphere, the temperature was raised at 5°C / min, and calcined at 500°C for 4h. After 210r / min, 1h ball milling. The particle size of the obtained silicon-carbon composite particles is 0.5 μm, which is marked as A2.

[0055] Step 2. Heat the asphalt to 100°C to turn the asphalt into a liquid state, add A2, the mass ratio of A2 to asphalt is 1:1, knead and stir at 100°C for 1 hour. After it is taken out and cooled, it is crushed by a pulverizer and marked as B2.

[0056] Step 3. Use a high-speed mixer at 300r / min to mix B2 and artificial graphite particles with a particle size of 12um, and the ratio of B2 to...

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Abstract

The invention provides a cathode active material for a lithium ion battery, a method for preparing the cathode active material and a cathode and the battery with the cathode active material. The cathode active material comprises graphite particles and silicon carbon composite particles. The silicon carbon composite particles are dispersed on the surfaces of the graphite particles, and the exposed surface areas of the graphite particles account for 80%-98% of the total surface areas of the graphite particles. The cathode active material, the method, the cathode and the lithium ion battery have the advantages that the problems of cracking, falling and the like of outer-layer silicon carbon materials of composite materials with inner-layer graphite particles and outer-layer silicon carbon composite particles due to uneven expansion in charge and discharge procedures of lithium ion batteries in the prior art can be solved by the aid of the cathode active material, excellent electric contact can be maintained, and the cycle performance of the battery can be improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a lithium ion battery negative electrode active material and a preparation method thereof, a negative electrode containing the negative electrode active material and a battery. Background technique [0002] At present, the widely used negative electrode of lithium ion battery is mainly graphite. The theoretical capacity of graphite is 372mAh / g. It has good platform performance and low potential during charge and discharge, so it is an ideal negative electrode material. It has had very good results in past applications. However, as many new applications of lithium batteries, carbon materials such as graphite have gradually exposed some disadvantages: limited capacity, low high-rate charge-discharge capability, and poor low-temperature performance. In particular, the performance of high-current charging is not good, because the voltage platform of graphite is low, and the pote...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/36H01M4/38H01M4/583H01M10/0525
CPCH01M4/13H01M4/366H01M4/386H01M4/583H01M10/0525Y02E60/10
Inventor 朱光耀刘会权
Owner BYD CO LTD
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