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Graphite negative electrode material and preparation method and application thereof

A graphite negative electrode and graphite technology, applied in the direction of negative electrodes, battery electrodes, active material electrodes, etc., can solve the problems of the coating layer being damaged, easy to agglomerate, and unable to achieve the coating effect, etc., and achieve constant current charging ratio improvement Effect

Pending Publication Date: 2021-09-24
江西紫宸科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with uncoated graphite, the graphite anode coated with pyrolytic carbon has greatly improved in terms of reversible capacity, cycle performance, and low-temperature rate performance. However, in the existing pyrolytic carbon coating process, high temperature Pyrolysis or high temperature curing is prone to particle bonding and uneven coating
The improvement of the performance of graphite materials by different coating processes has reached a bottleneck, and it is difficult to meet the performance requirements of the current lithium-ion battery industry for graphite anodes (the first reversible capacity is higher than 360mAh / g, and the first Coulombic efficiency is higher than 92%). Poor secondary stability and high production cost
[0006] CN103647055A discloses a negative electrode material of epoxy resin modified graphite and a preparation method thereof, by grinding, curing at high temperature, carbonizing and pulverizing organic silicon modified epoxy resin and natural graphite to obtain a modified epoxy resin Although the natural graphite material can prevent the co-embedding of large-volume solvent molecules, high-temperature pyrolysis is easy to agglomerate, and crushing will also destroy the coating effect, resulting in uneven coating on the graphite surface and destruction of the coating layer. achieve good wrapping effect

Method used

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  • Graphite negative electrode material and preparation method and application thereof
  • Graphite negative electrode material and preparation method and application thereof
  • Graphite negative electrode material and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] This embodiment provides a hard carbon-coated graphite negative electrode material.

[0059] The preparation method of described graphite negative electrode material is as follows:

[0060] (1) Mix tetrahydrophthalic acid epoxy resin and curing agent uniformly with a mass ratio of 100:70 to obtain liquid B, wherein the curing agent is hexacyanophthalic anhydride and triethylenetetramine in a weight ratio of 1:1 premixed mixture;

[0061] (2) Liquid B is wetted on the surface of artificial graphite powder with a median particle size of 5 μm by the action of shear force to obtain resin and graphite composite material A, and the mass ratio of artificial graphite powder to liquid B is 100:3;

[0062] (3) Put composite material A in a carbonization furnace, heat up to 700°C at a heating rate of 1°C / min in a nitrogen atmosphere for sintering for 4 hours, then cool to room temperature, and use a 600-mesh screen after mixing with a mixing device Sieve to obtain the hard carbo...

Embodiment 2

[0064] This embodiment provides a hard carbon-coated graphite negative electrode material.

[0065] The preparation method of described graphite negative electrode material is as follows:

[0066] (1) Fully mix the water-based bisphenol-A epoxy resin and water in a mass ratio of 100:100 to obtain Liquid A; Ratio, add curing agent to liquid A and mix evenly to obtain liquid B;

[0067] (2) Liquid B is wetted on the surface of natural graphite powder with a median particle size of 10 μm by the effect of extrusion force to obtain resin and graphite composite material A, and the mass ratio of artificial graphite powder to liquid B is 2:1;

[0068] (3) Put composite material A in a carbonization furnace, heat up to 850°C at a heating rate of 3°C / min under nitrogen atmosphere for sintering for 12 hours, then cool to room temperature, and use a 500-mesh screen after mixing with a mixing equipment Sieve to obtain the hard carbon-coated graphite negative electrode material.

Embodiment 3

[0070] This embodiment provides a hard carbon-coated graphite negative electrode material.

[0071] The preparation method of described graphite negative electrode material is as follows:

[0072] (1) Fully mix o-cresol novolac epoxy resin and water at a mass ratio of 100:30 to obtain liquid A; Mass ratio, adding curing agent to liquid A and mixing evenly to obtain liquid B;

[0073] (2) Liquid B is wetted on the surface of artificial graphite powder with a median particle size of 25 μm by the effect of friction to obtain resin and graphite composite material A, and the mass ratio of artificial graphite powder to liquid B is 100:15;

[0074] (3) Put composite material A in a carbonization furnace, heat up to 1100°C at a heating rate of 5°C / min under nitrogen atmosphere for sintering for 8 hours, then cool to room temperature, and use a 400-mesh screen after mixing with a mixing equipment Sieve to obtain the hard carbon-coated graphite negative electrode material.

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Abstract

The invention provides a graphite negative electrode material and a preparation method and application thereof. The graphite negative electrode material is a carbon layer coated graphite negative electrode material, and the carbon layer is a hard carbon coating layer; the graphite negative electrode material has two exothermic peaks when being burnt at the temperature of 600 to 1000 DEG C, and the exothermic peaks are respectively positioned in the range of 800 to 900 DEG C and the range of 900 to 1000 DEG C. The preparation method comprises the following steps: (1) mixing epoxy resin with a curing agent to obtain a mixed solution, and compounding the mixed solution with graphite by using mechanical force to obtain a composite material; and (2) carbonizing the composite material to obtain the graphite negative electrode material. The epoxy resin is wetted and coated on the surface of the graphite under the action of mechanical force and reacts with the curing agent to directly obtain the thermosetting resin on the surface of the graphite, and the graphite negative electrode material uniformly coated with hard carbon is obtained after carbonization, so that the specific surface area of the graphite negative electrode material can be effectively reduced, the charging rate is improved, and rapid charging is realized.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a graphite negative electrode material and a preparation method and application thereof. Background technique [0002] In recent years, in order to cope with the huge changes in the automobile industry, the electric vehicle market has developed rapidly, but the mileage anxiety still plagues drivers, especially because the charging time is too long, which makes the scarce charging piles more scarce. The lithium-ion battery with high charging rate shortens the charging time, which can meet the market demand. [0003] The key to improving the charging rate of lithium batteries lies in the innovation of raw materials. Graphite has become the mainstream negative electrode material in the current market due to its good chemical stability and electrical properties. However, in the process of lithium intercalation, Li + It is not possible to embed graphite sheets from the ba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/583H01M10/0525
CPCH01M4/366H01M4/583H01M10/0525H01M2004/027H01M2004/021Y02E60/10
Inventor 李春姜武刘东任李辉刘芳冯苏宁
Owner 江西紫宸科技有限公司
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