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Preparation method of low-expansion long-circulating natural graphite

A natural graphite, long-cycle technology, applied in the direction of graphite, etc., can solve the problems of unsuitable for high-current charging and discharging, long diffusion path of lithium ions, poor fast charging and discharging performance, etc., and achieve good high-current charging and discharging performance and excellent comprehensive performance , The effect of stable product properties

Active Publication Date: 2017-02-15
NINGBO SHANSHAN NEW MATERIAL TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the defects of these modification methods are very obvious. For example, due to the good crystallinity of graphite and the 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 lithium ion diffusion path and are not suitable for large currents. Charge and discharge; the raw material particles used in these methods are generally large and have obvious anisotropy, so the fast charge and discharge performance is poor; the utilization rate of raw materials in these methods is low, and the general shaping yield is only about 50%; these methods are all based on raw materials Based on shaping treatment, in order to pursue better sphericity, the treatment process is troublesome and the treatment cost increases

Method used

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  • Preparation method of low-expansion long-circulating natural graphite
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  • Preparation method of low-expansion long-circulating natural graphite

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Experimental program
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Effect test

Embodiment 1

[0032] Microcrystalline graphite powder: D50 is 9.1μm, 200kg;

[0033] Graphitizable binder: petroleum pitch powder below 5μm, 60kg;

[0034] Under stirring, alternately add microcrystalline graphite powder and petroleum pitch powder into the mixing pot and mix. 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 conduct high-temperature treatment of graphitization at 2800 ° C for 36 hours, mix and sieve, and obtain particles with a particle size D50 of 10.8μm low-expansion long-cycle natural graphite has a half-cell capacity of 367.5mAh / g and an initial efficiency of 95.8%.

Embodiment 2

[0036] Microcrystalline graphite powder: D50 is 9.5μm, 200kg;

[0037] Graphitizable binder: petroleum pitch powder below 5μm, 20kg;

[0038] Under stirring, alternately add microcrystalline graphite powder and petroleum pitch powder into the mixing pot and mix. 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 conduct high-temperature treatment of graphitization at 2900 ° C for 48 hours, mix and sieve, and obtain particles with a particle size D50 of 10.3μm low-expansion long-cycle natural graphite, its half-cell capacity is 368.1mAh / g, and the first-time efficiency is 96.2%, see figure 1 and figure 2 .

Embodiment 3

[0040] Microcrystalline graphite powder: D50 is 5.1μm, 200kg;

[0041] Graphitizable binder: coal tar pitch powder below 5μm, 40kg;

[0042] Under stirring, alternately add microcrystalline graphite powder and coal tar pitch powder to the mixing pot and mix. 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 conduct high-temperature treatment of graphitization at 3000 ° C for 48 hours, mix and sieve, and obtain particles with a particle size D50 of 7.4μm low-expansion long-cycle natural graphite, its half-cell capacity is 370.0mAh / g, and the first-time efficiency is 95.6%.

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Abstract

The invention belongs to the technical field of graphite preparation, and more specifically relates to a preparation method of a low-expansion long-circulating natural graphite. The preparation method comprises following steps: 1, smashing shaping is carried out; 2, mixing is carried out; 3, low temperature heat treatment is carried out; 4, graphitization high temperature treatment is carried out; and 5, material mixing sieving is carried out. An adhesive convenient for graphitization is an ingredient or a mixture of ingredients selected from petroleum asphalt, coal pitch, phenolic resin, epoxy resin, furane resin, or furfural resin; and the using amount of the adhesive accounts for 10 to 30% of the weight amount of a microcrystalline graphite raw material. Compared with the prior art, the preparation method possesses following advantages: the preparation method is simple and feasible, and is suitable for industrialized production; prepared graphite is low in expansion performance, large in discharge capacity, and long in cycle life; and the comprehensive properties of button cells prepared from the low-expansion long-circulating natural graphite are excellent.

Description

technical field [0001] The invention relates to the technical field of graphite preparation, in particular to a method for preparing low-expansion long-cycle natural 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 mate...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/21
CPCY02E60/10
Inventor 杨再颖谢秋生肖玮丁晓阳王旭峰
Owner NINGBO SHANSHAN NEW MATERIAL TECH
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