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Foamy graphite flake for lithium battery cathode and preparation method thereof

A technology of foamed graphite and lithium batteries, applied in battery electrodes, graphite, secondary batteries, etc., can solve the problem of weakening the electrolyte absorption capacity of the negative electrode sheet, reducing the energy density of lithium-ion batteries, and increasing the polarization of intercalation and extraction and other problems to achieve the effect of overcoming fragility, enhancing strength and toughness, and increasing porosity

Inactive Publication Date: 2019-05-10
DONGGUAN HONGYI THERMAL CONDUCTMTY MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

The increase in the degree of graphitization will reduce the interlayer spacing of graphite, resulting in an increase in the polarization of lithium ions intercalated and extracted in the negative electrode sheet.
Excessively high compaction density of the negative electrode sheet will reduce the porosity of the negative electrode sheet, greatly weakening the ability of the negative electrode sheet to absorb the electrolyte, and increasing the polarization of the lithium-ion battery during low temperature and high rate charge and discharge.
[0005] The industry has improved the process of high compaction density. For example, Chinese Patent Application Publication No. CN102195029A discloses a lithium-ion battery and its negative pole piece, which adopts a composite graphite layer process, but this process still reduces to a certain extent. The energy density of lithium-ion batteries

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  • Foamy graphite flake for lithium battery cathode and preparation method thereof

Examples

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Comparison scheme
Effect test

Embodiment 1

[0025] A kind of foam graphite sheet that is used for lithium battery negative electrode, its preparation method comprises the steps:

[0026] 1) Disperse graphite powder with a particle size of 0.2 μm, lithium carbonate particles with a particle size of 0.1 μm, and polyvinylidene fluoride in an N-methylpyrrolidone solvent at a mass ratio of 0.1:0.1:0.02 to obtain a graphite slurry;

[0027] 2) Coating the graphite slurry on the copper foil substrate, drying at a temperature of 1300° C., and forming a foamed graphite carbon layer on the copper foil substrate after the lithium carbonate is gasified;

[0028] 3) Soak the copper foil substrate coated with the foamed graphite carbon layer in a ferric chloride solution with a concentration of 2mol / L, and after the copper foil substrate is dissolved, clean the foamed graphite carbon layer with deionized water Afterwards, drying treatment is carried out to obtain foamed graphite sheets.

Embodiment 2

[0030] A kind of foam graphite sheet that is used for lithium battery negative electrode, its preparation method comprises the steps:

[0031] 1) Disperse graphite powder with a particle size of 5 μm, lithium carbonate particles with a particle size of 10 μm, and polyvinylidene fluoride at a mass ratio of 0.5:0.8:0.1 in N,N-dimethylformamide solvent to obtain graphite slurry material;

[0032] 2) Coating the graphite slurry on a copper foil substrate, drying at a temperature of 1500° C., and forming a foamed graphite carbon layer on the copper foil substrate after the lithium carbonate is gasified;

[0033] 3) Soak the copper foil substrate coated with the graphite foam layer in a silver nitrate solution with a concentration of 3.5mol / L, and after the copper foil substrate is dissolved, clean the graphite carbon layer foam with deionized water , and dried to obtain foamed graphite sheets.

Embodiment 3

[0035] A kind of foam graphite sheet that is used for lithium battery negative electrode, its preparation method comprises the steps:

[0036] 1) Disperse graphite powder with a particle size of 2 μm, lithium carbonate particles with a particle size of 5 μm, and polyvinylidene fluoride at a mass ratio of 0.3:0.5:0.06 in N,N-dimethylformamide solvent to obtain graphite slurry material;

[0037] 2) Coating the graphite slurry on the copper foil substrate, drying at a temperature of 1350° C., and forming a foamed graphite carbon layer on the copper foil substrate after the lithium carbonate is gasified;

[0038] 3) Soak the copper foil substrate coated with the foamed graphite carbon layer in a mercury sulfate solution with a concentration of 3.5mol / L. After the copper foil substrate is dissolved, use deionized water to clean the foamed graphite carbon layer , and dried to obtain foamed graphite sheets.

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Abstract

The invention discloses a preparation method for a foamy graphite flake for a lithium battery cathode. The preparation method comprises the following steps: 1) dispersing graphite powder, lithium carbonate grains and polyvinylidene fluoride at mass ratio of (0.1-0.5):(0.1-0.8):(0.02-0.1) into a solvent, thereby acquiring graphite slurry; 2) coating the graphite slurry on a base plate, drying at 1300-1500 DEG C, gasifying lithium carbonate and then forming a foamy graphite carbon layer on the base plate; 3) soaking the base plate coated with the foamy graphite carbon layer into a solution, andthen post-treating the foamy graphite carbon layer after the base plate is dissolved, thereby acquiring the foamy graphite flake. According to the invention, lithium carbonate grains and polyvinylidene fluoride are added into graphite powder, so that the toughness and strength of the foamy graphite flake can be enhanced; the porosity of graphite flake layer can be promoted in the manner of occupying by gasifying lithium carbonate, so that the absorbing ability of cathode to electrolyte and energy density of lithium ion battery can be promoted.

Description

technical field [0001] The invention relates to the technical field of graphite sheets, in particular to a foamed graphite sheet used for a negative electrode of a lithium battery and a preparation method thereof. Background technique [0002] With the advancement of technology, the application of mobile devices is becoming more and more extensive. Due to the rapid growth of mobile devices, there is a great demand for high energy density batteries. [0003] Anode materials are a key component of lithium-ion batteries, which directly affect key indicators such as battery energy density, cycle life, and safety performance. In the future, anode materials for lithium-ion batteries must be developed in the direction of high capacity in order to solve the problem of existing battery energy density. low problem. [0004] At present, the commercial negative electrode active material is mainly graphite, and the methods to increase its energy density mainly include increasing the de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/21H01M4/587H01M10/0525
CPCY02E60/10
Inventor 朱全红施立毛周招团
Owner DONGGUAN HONGYI THERMAL CONDUCTMTY MATERIAL CO LTD