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Method for modifying surface of graphite particle

A graphite particle and surface modification technology, applied in chemical instruments and methods, inorganic pigment treatment, fibrous fillers, etc., can solve the problems of unfavorable large-scale production, small reversible capacity, cumbersome process steps, etc., to improve cycle performance and Reversible capacity, good cycle performance and safety performance, and the effect of improving safety performance

Inactive Publication Date: 2004-10-27
UNIV OF SCI & TECH OF CHINA
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Problems solved by technology

However, the process of this method is complicated, and the machine for crushing graphite particles is unique and expensive, which increases the cost of industrial production.
In addition, this method cannot improve the safety performance of graphite anode materials
CN1366361A proposes to coat a layer of lithium carbonate passivation film on the surface of graphite to prevent co-intercalation of solvated lithium ions. This method needs to be carried out under negative pressure, the process steps are cumbersome, the improvement of reversible capacity is small, and the cost is very high , not conducive to large-scale industrial production
[0007] The above-mentioned modification methods only solve one aspect of the electrical properties of graphite as the negative electrode active material.

Method used

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  • Method for modifying surface of graphite particle
  • Method for modifying surface of graphite particle
  • Method for modifying surface of graphite particle

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Prepare a stainless steel autoclave with polytetrafluoroethylene as the liner, and a constant temperature oven with a tolerance temperature of at least 140°C. Put 5 grams of graphite powder (CZ-1) (provided by Lanzhou Carbon Co., Ltd.) into a polytetrafluoroethylene liner with a volume of about 48ml, add 23.54ml of deionized water, and stir with a glass rod to fully wet the graphite powder to form a suspension liquid. According to the volume ratio is H 2 SO 4 : HNO 3 :CH 3 COOH:H 2 Slowly add concentrated sulfuric acid (98%), concentrated nitric acid (67%), and glacial acetic acid in the ratio of O=1:1:1:3, stir well, cover the inner tank cover, then tighten the stainless steel outer cover, and put it in a constant temperature Oven, at a temperature of 95°C, continuously soak for 72 hours, and then naturally cool to room temperature. Filter, then soak the graphite particles with deionized water for 4 hours, filter and wash again, and when the filtrate pH~7, dry th...

Embodiment 2

[0033] According to the same steps and the same proportion of Example 1 to modify the morphology of graphite particles, the graphite powder (1 μm-10 μm) purchased from Qingdao Huatai Company was used instead, and the reaction temperature was adjusted from 95 ° C to 120 ° C. From the scanning electron microscope photos, graphite The sharp parts on the surface of the particles are dissolved, which is similar to the morphology of the modified graphite particles obtained in Example 1.

Embodiment 3

[0035] In order to evaluate the electrochemical performance of graphite particles after morphology modification, the modified graphite was made into a half-cell. Its production process is as follows:

[0036]According to the mass ratio of graphite: polyvinylidene fluoride = 9: 1, the shape-modified graphite obtained in Example 1 is mixed, and an appropriate amount of NMP (N-methyl-2-pyrrolidone) is added, mixed thoroughly, and then uniformly Coated on copper foil, dried at 70°C for two hours, removed NMP from the copper foil, pressed the negative electrode film to 70% of the original thickness with a roller press, and punched it into an electrode film with a diameter of 31.75mm; follow the same process , the unmodified graphite (CZ-1) provided by Lanzhou Carbon Company was prepared into an electrode film, waiting to be assembled into a battery.

[0037] performance

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Abstract

A process for modifying the surface of graphite particles used for the negative electrode of lithium battery includes adding graphite powder to high-pressure reactor, adding deionized water, stirring, adding inorganic acid chosen from concentrated sulfuric acid, nitric acid, phosphoric acid, hydrochloride acid, and glacial acetic acid, heating to 80-140 deg.C, holding the temp for 10 hrs, natural cooling, filtering, immersing in deionized water, pumping filter, washing until pH=7 and low-temp baking.

Description

1. Technical field [0001] The invention relates to a modification method for negative electrode materials used in nonaqueous storage batteries, in particular to a surface modification method for negative electrode graphite particles of lithium batteries. 2. Background technology [0002] Non-aqueous storage batteries such as nickel metal hydride, nickel cadmium, lithium ion and other batteries are the energy pillar products of the communication and information industry in the 21st century. They are mainly used in mobile phones, notebook computers, digital cameras, etc. Lithium-ion batteries have the advantages of high energy density, high working voltage, and long life. They are the mainstream direction of non-aqueous batteries in the future. People expect them to be applied in more fields, such as electric vehicles, hybrid vehicles or other high-power energy devices. . [0003] The initial lithium battery uses metal lithium as the negative electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09C3/06
Inventor 陈春华张晋
Owner UNIV OF SCI & TECH OF CHINA
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