Modified natural graphite particle and method for producing same

A natural graphite and manufacturing method technology, applied in the direction of graphite, active material electrodes, electrical components, etc., can solve the problems of large irreversible capacity and low filling density

Inactive Publication Date: 2012-12-26
NIPPON STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the particles of these natural graphites are in the form of scales (plates), they have disadva...

Method used

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  • Modified natural graphite particle and method for producing same
  • Modified natural graphite particle and method for producing same
  • Modified natural graphite particle and method for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] (Example 1) Example 1 is the modified natural graphite particles 16 described above.

Embodiment 2

[0104] (Examples 2 to 5) Examples 2 to 5 are particles obtained by using the same manufacturing steps as the above-mentioned modified natural graphite particles 16, and are for explaining the case of using particles with different average particle diameters (the preparation method is as above.) example of. Example 2 is the particles processed by the mechanical milling device 30 for Comparative Example 4. Similarly, Example 3 corresponds to Comparative Example 5, Example 4 corresponds to Comparative Example 6, and Example 5 corresponds to Comparative Example 7.

[0105] Regarding circularity, average particle diameter and specific surface area, comparing Examples 2 to 5 with the corresponding Comparative Examples 4 to 7, no major difference was found.

[0106] Regarding the tap density, when Examples 2 to 5 were compared with Comparative Examples 4 to 7 corresponding thereto, it was found that any of the tap densities in Examples 1 to 5 were improved. The tap density is prefer...

Embodiment 6

[0112] (Example 6) 20% by mass of coal tar pitch powder having an average particle diameter of 20 μm was mixed with the modified natural graphite particles of Example 4, and heat-treated at 1000° C. for 1 hour in a nitrogen gas flow. The pitch powder is melted during the heat treatment to wet the surface of the modified natural graphite particles, and then becomes a carbonaceous material formed of low-crystalline carbon by carbonization. In this way, a carbonaceous material adhered to the surface of the modified natural graphite particles was obtained.

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Abstract

Disclosed is a natural graphite particle forming a negative electrode active substance for a non-aqueous electrolyte secondary battery, characterized by having a circularity of 0.93 - 1.0 and a surface roughness of 1.5% of the largest particle diameter. Also disclosed is a method for producing modified particles of natural graphite in which grinding and spheronizing are carried out by applying an impact force to the natural graphite particles and there is a process for obtaining intermediate particles with a circularity of 0.93 - 1.0 as well as a process for obtaining the modified natural graphite particles by performing surface smoothing using mechanical milling of the intermediate particles obtained.

Description

technical field [0001] The invention relates to modified natural graphite particles for negative poles of non-aqueous electrolyte secondary batteries, in particular to modified natural graphite particles for negative poles of lithium ion secondary batteries. [0002] In the present invention, "negative electrode active material" refers to one of the materials constituting the negative electrode of the non-aqueous secondary battery, which accepts or releases positively charged particles (eg, lithium ions). A coating layer formed of a negative electrode mixture that is a mixture of the negative electrode active material and a binder is formed on a current collector formed of a conductive material, and the coating layer is subjected to molding processing such as compression to obtain a plate as The negative electrode plate of the negative electrode member. [0003] In the present invention, "modified natural graphite particles" refers to particles obtained by subjecting particle...

Claims

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Application Information

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IPC IPC(8): C01B31/04H01M4/36H01M4/587
CPCY02E60/12H01M4/587H01M4/0402C01P2006/11C01P2006/19H01M4/1393C01P2006/10H01M4/133C01B31/04C01B32/21Y02E60/10C01P2004/32H01M2004/027
Inventor 山本浩司永田辰夫西原克浩禰宜教之八内昭博藤原彻
Owner NIPPON STEEL CORP
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