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Preparation method of low expansion graphite

A low-expansion, graphite-based technology, applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of poor fast charge and discharge performance, long lithium ion diffusion path, troublesome processing procedures, etc., and achieve high current charge and discharge performance Good, the preparation method is simple and feasible, and the effect of stable product properties

Inactive Publication Date: 2016-12-21
SHANGHAI SHANSHAN TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the defects of these modification methods are very obvious
For example, due to the good crystallinity of graphite and well-developed layer orientation, lithium ions are only allowed to intercalate and extract along the boundaries of graphite. Therefore, these modification methods have a long diffusion path for lithium ions and are not suitable for high-current charging and discharging; the raw material particles used in these methods are generally relatively small. Large, obvious anisotropy, so the rapid charge and discharge performance is poor; the raw material utilization rate of these methods is low, and the general shaping yield is only about 50%; these methods are based on raw material shaping treatment, in order to pursue better Sphericity, troublesome processing procedures, increased processing costs

Method used

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  • Preparation method of low expansion graphite
  • Preparation method of low expansion graphite
  • Preparation method of low expansion graphite

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Flake graphite raw material: crush the flake graphite raw material into a powder with a D50 of 9.1 μm, 200kg;

[0029] Graphitizable binder: petroleum asphalt powder with a particle size below 5 μm, 60kg;

[0030] Graphitization catalyst: SiO 2 , 16kg;

[0031] While stirring, alternately add flake graphite powder, petroleum pitch powder, SiO 2 Add to a mixing pot and combine. Under the protection of nitrogen, heat treatment at a low temperature of 500 ° C for 16 hours, then cool the reaction product to room temperature, and then carry out a high temperature treatment of catalytic graphitization at 2800 ° C for 36 hours, mix and sieve, and obtain particles with a particle size D50 of The low-expansion graphite of 17.8 μm has a half-cell capacity of 367.5mAh / g and an initial efficiency of 95.8%.

Embodiment 2

[0033] Flake graphite raw material: crush the flake graphite raw material into a powder with a D50 of 9.5 μm, 200kg;

[0034] Graphitizable binder: petroleum asphalt powder with a particle size below 5 μm, 20kg;

[0035] Graphitization catalyst: SiC, 6kg;

[0036] While stirring, alternately add flake graphite powder, petroleum pitch powder, and SiC into the mixing pot for mixing. Under the protection of nitrogen, heat treatment at a low temperature of 500°C for 16 hours, then cool the reaction product to room temperature, then carry out high-temperature treatment of catalytic graphitization at 3000°C for 48 hours, mix and sieve, and obtain particles with a particle size D50 of 18.3μm low-expansion graphite, its half-cell capacity is 368.1mAh / g, and the first-time efficiency is 96.2%.

Embodiment 3

[0038] Flake graphite raw material: crush the flake graphite raw material into a powder with a D50 of 5.1 μm, 200kg;

[0039] Graphitizable binder: petroleum asphalt powder with a particle size below 5 μm, 40kg;

[0040] Graphitization catalyst: SiO 2 , 10kg;

[0041] While stirring, alternately add flake graphite powder, petroleum pitch powder, SiO 2 Add to a mixing pot and combine. Under the protection of nitrogen, heat treatment at a low temperature of 800 ° C for 10 hours, then cool the reaction product to room temperature, and then carry out high-temperature treatment of catalytic graphitization at 3200 ° C for 48 hours, mix and sieve, and obtain particles with a particle size of D50 It is 17.4μm low-expansion graphite, its half-cell capacity is 370.0mAh / g, and its first-time efficiency is 95.6%.

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Abstract

The invention relates to the technical field of a graphite negative electrode material, in particular to a preparation method of low expansion graphite. The preparation method is characterized by comprising the following steps of (1) smashing and shaping flake graphite raw material to grain sizes with D50 being 5-10 micrometers; (2) mixing the flake graphite raw material, an adhesive easy to be graphitized and a graphitized catalyst; (3) performing low-temperature thermal processing for 10-20 hours at 300-800 DEG C under protection of inert gas, and cooling the mixture to a room temperature; (4) performing catalytic graphitization high-temperature processing for 24-48 hours at 2,800-3,200 DEG C under the protection of inert gas; and (5) sieving the mixture, and obtaining the low expansion graphite. Compared with the prior art, the preparation method is simple and practical and is suitably used for industrial production, the prepared graphite is low in expansion, large in discharge capacity and high in cycle performance, and a button cell prepared from the graphite is excellent in integral performance.

Description

technical field [0001] The invention relates to the technical field of graphite negative electrode materials, in particular to a preparation method of low-expansion graphite. Background technique [0002] In recent years, with the miniaturization of electronic devices, there has been an increasing need for a secondary battery with a larger capacity. Of particular interest are lithium-ion batteries, which have a higher energy density than nickel-cadmium or nickel-metal hydride batteries. Although extensive research has been conducted on increasing the battery capacity, further increases in battery capacity are required as the requirements for battery performance increase. [0003] As negative electrode materials for lithium ion batteries, granular materials such as metals or graphite have been studied. With the increase of battery capacity, it is especially necessary to use higher electrode density (such as 1.75g / cm 3 or higher than 1.75g / cm 3 ) The negative electrode mat...

Claims

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Application Information

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IPC IPC(8): H01M4/587H01M10/0525C01B31/04
CPCH01M4/587H01M10/0525Y02E60/10
Inventor 杨再颖谢秋生仲林丁晓阳杜辉玉王旭峰娄文君
Owner SHANGHAI SHANSHAN TECH CO LTD
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