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Modified natural graphite and preparation method and application thereof

A natural graphite, modified technology, applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of poor rate performance, uneven carbon coating on the surface of modified graphite, insufficient doping, etc., to achieve It is beneficial to insert and extract, improve graphite interlayer corrosion, and improve cycle performance

Inactive Publication Date: 2016-06-01
SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method reduces the powder resistance as a whole, it is difficult to achieve the expected effect without treatment on the surface of spherical natural graphite; Chinese patent CN103972508A adopts inorganic element doping and nitrogen-containing organic matter to coat modified natural graphite, and the Coulombic efficiency is improved for the first time. The rate performance is improved, but the cycle performance is average, and there are shortcomings such as insufficient doping due to the small amount of inorganic elements in the modification process, uneven carbon coating on the surface of modified graphite, etc.
Japanese patent JP20020422816 uses chemical vapor deposition to coat graphite materials, which can make the coating material more uniform on the surface of the material, reduce the powder resistance and specific surface area of ​​the material, and improve the ability of the material to resist electrolyte, but at the same time it also makes the process It becomes complicated and the cost is high; Chinese patent CN1585172A and Chinese patent CN1624955A use pitch to coat the graphite material and graphitize it at high temperature, which reduces the specific surface area of ​​the material, effectively prevents solvent co-insertion, and improves the first Coulombic efficiency. However, its rate performance is not good, and the cycle performance has not been completely improved.

Method used

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  • Modified natural graphite and preparation method and application thereof
  • Modified natural graphite and preparation method and application thereof
  • Modified natural graphite and preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0030] The modified natural graphite raw material prepared in this example, the specific method is to intercalate the natural graphite with concentrated phosphoric acid for 6 hours at 180°C, and then coat it with diethylamine. The coating of diethylamine The amount is about 20%.

[0031] The specific preparation process is as follows: get 60g natural graphite (particle size D 50 =16.9μm), add 30g of concentrated phosphoric acid with a concentration of 85.11%, stir, mix evenly, treat at a constant temperature in a blast drying oven at 180°C for 6h, take it out after natural cooling; add 12g of diethylamine to the obtained sample, stir , mix evenly, then put the sample into the quartz porcelain boat, push the quartz porcelain boat into the tube furnace, under N 2 Under the atmosphere, the temperature was raised to 900°C at a rate of 10°C / min, treated at a constant temperature for 10 hours, cooled naturally to room temperature, and then taken out to obtain a modified natural gra...

Embodiment 2

[0037] Take 60g natural graphite (particle size D 50 = 16.9μm), add 15g of concentrated sulfuric acid with a concentration of 98wt%, stir, mix evenly, treat at a constant temperature in a blast drying oven at 200°C for 2h, take it out after natural cooling; add 20g of formamide to the obtained sample, stir, Mix well, then put the sample into the quartz porcelain boat, push the quartz porcelain boat into the tube furnace, 2 Under the atmosphere, the temperature was raised to 1500°C at a rate of 5°C / min, treated at a constant temperature for 1 hour, cooled naturally to room temperature, and then taken out to obtain a modified natural graphite sample. The preparation of the button cell was the same as in Example 1, and the electrochemical performance test results are listed in Table 1.

Embodiment 3

[0039] Take 60g natural graphite (particle size D 50 =16.9μm), add 25g of concentrated hydrochloric acid with a concentration of 37.5wt%, stir, mix evenly, and then treat it at a constant temperature in a blast drying oven at 90°C for 16h, take it out after natural cooling, put the sample into a quartz porcelain boat, Push the quartz porcelain boat into the tube furnace, at N 2 Under the atmosphere, the temperature was raised to 500°C at a rate of 15°C / min, treated at a constant temperature for 14 hours, cooled naturally to room temperature, and then taken out to obtain a modified natural graphite material. The preparation of the button cell was the same as in Example 1, and the electrochemical performance test results are listed in Table 1.

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Abstract

The invention discloses modified natural graphite and a preparation method and an application thereof. The method comprises the following specific steps: firstly, mixing a graphite material with an intercalator evenly at the ratio, carrying out constant-temperature treatment on the mixed slurry at 90-200 DEG C for 1-16 hours to obtain an intercalated graphite material; adding an organic amine liquid to the intercalated graphite material, and stirring and mixing the organic amine liquid and the intercalated graphite material evenly; enclosing the obtained sample into a crucible, carrying out high-temperature thermal treatment in an inert gas atmosphere at 500-1500 DEG C for 0.5-14h, naturally cooling the sample and then taking out the sample to obtain the modified natural graphite material. The method is simple in process, mild in reaction condition, easy to control, relatively low in cost and beneficial to industrial implementation; and the obtained modified natural graphite is good in rate capability and cycle performance.

Description

technical field [0001] The invention relates to the field of preparation of negative electrode materials for lithium ion batteries, in particular to a modified natural graphite, a preparation method and an application thereof. Background technique [0002] Natural graphite is widely used as an anode material for lithium-ion batteries due to its advantages such as small specific surface area, high theoretical capacity, stable charge-discharge platform, and low cost. However, natural graphite has a high selectivity to the electrolyte, and its high-current charge-discharge performance is poor. In addition, during the first charge-discharge process, the solvated lithium ions will be inserted into the graphite layer to reduce and decompose to produce new substances. When the generated stress exceeds the weak van der Waals force between the graphite layers, it will cause the graphite layer to peel off, resulting in a decrease in the charge and discharge performance of the battery,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/587H01M10/0525
CPCH01M4/366H01M4/587H01M10/0525Y02E60/10
Inventor 王利军刘肖强张素娜
Owner SHANGHAI SECOND POLYTECHNIC UNIVERSITY
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