Negative electrode active material for lithium secondary battery, preparation method of the same, and lithium secondary battery containing the same

A cathode active material, lithium secondary battery technology, applied in the direction of active material electrodes, secondary batteries, secondary battery components, etc., can solve problems such as the inability to achieve high electrode density, and the inability to fully meet the characteristics of high capacity and cycle capacity

Inactive Publication Date: 2011-05-25
POSCO CHEMTECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, in the preparation of cathode active materials, high electrode density of 1.7 g / cc or more cannot be achieved even by surface-treating natural graphite with low-crystalline carbon or amorphous graphite, so high capacity and cycle capacity characteristics cannot be fully satisfied

Method used

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  • Negative electrode active material for lithium secondary battery, preparation method of the same, and lithium secondary battery containing the same
  • Negative electrode active material for lithium secondary battery, preparation method of the same, and lithium secondary battery containing the same
  • Negative electrode active material for lithium secondary battery, preparation method of the same, and lithium secondary battery containing the same

Examples

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Effect test

Embodiment 1

[0041] In spherical natural graphite, a mixture was prepared by dry mixing 5% by weight of pitch and 2% by weight of carbon fiber (VaporGrowth Carbon Fiber, VGCF) at high speed for about 10 minutes. The 1st and 2nd firings were carried out at the same temperature for 1 hour, respectively. Next, fine powder is classified and removed, thereby producing a carbon material uniformly coated with pitch and carbon fibers.

[0042] Uncoated spherical natural graphite was added to the carbon material produced above, and uniformly mixed with a rotary mixer at a mixing ratio of 50%. The cathode active material prepared in this way of 100g is put into 500ml reactor, and after dropping into carboxymethylcellulose (CMC) aqueous solution and styrene-butadiene rubber (SBR) aqueous dispersion, utilize mixer to mix, And coated on the copper foil with a thickness of about 100μm. Afterwards, the product is dried and shaped by rolling. The bulk density of the manufactured electrode is 1.7g / cm 3...

Embodiment 2

[0044] The cathode active material was prepared in the same manner as in Example 1 above, except that the spherical natural graphite coated with amorphous graphite in whole or in part was mixed in a mixing ratio of 50%.

Embodiment 3

[0046] Except for mixing 20% ​​uncoated flake-shaped natural graphite, the cathode active material was prepared in the same manner as in Example 1 above.

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Abstract

The present invention relates to a negative electrode active material for a lithium secondary battery, a preparation method thereof, and a lithium secondary battery containing the negative electrode active material. The negative electrode active material for the lithium secondary battery according to the present invention is formed by mixing: a carbon material coated with vapor growth carbon fiber (VGCF) and amorphous graphite; and at least one kind of other carbon material selected from natural graphite, artificial graphite, amorphous-coated graphite, resin-coated graphite and amorphous carbon. According to the present invention, when the negative electrode active material is prepared, the carbon fiber is uniformly dispersed throughout the carbon material, and the carbon material is coated with the amorphous graphite and then mixed with other carbon materials, and thus high electrode density can be achieved. Accordingly, even with high electrode density, the invention can provide the negative electrode active material with excellent electrochemical properties such as charge / discharge efficiency and cycle characteristics.

Description

technical field [0001] The invention relates to a cathode active material for a lithium secondary battery and a manufacturing method thereof, and a lithium secondary battery using the cathode active material as a cathode, more specifically, to a cathode active material for a lithium secondary battery that can improve electrochemical characteristics Material and its manufacturing method, and a lithium secondary battery using the cathode active material as a cathode. Background technique [0002] In recent years, there has been a rapid increase in demand for secondary batteries that can be repeatedly charged and discharged as portable electronic devices for information and communication such as PDAs, mobile phones, and notebook computers, or as power sources for electric bicycles and electric vehicles. In particular, the performance of products such as portable electronic devices and electric vehicles is affected by the secondary battery as a core component, so the requirement...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M10/36
CPCY02E60/12H01M4/587H01M4/362H01M4/364H01M10/052Y02E60/10H01M4/58H01M4/02H01M10/02
Inventor 韩贞敏吴政勳金宗成廉哲韩京熙武内正隆须藤彰孝外轮千明
Owner POSCO CHEMTECH CO LTD
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