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A kind of isotropic graphite negative electrode material and preparation method thereof

An isotropic, negative electrode material technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of large irreversible capacity loss, cycle performance decline, graphite layer peeling, etc., to achieve the effect of easy industrialization and improved cycle performance

Inactive Publication Date: 2011-12-14
SHENZHEN XIANGFENGHUA TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Natural graphite is widely used as a negative electrode material for lithium-ion batteries, but the compatibility between natural graphite and electrolyte is poor, and the graphite layer is prone to peeling off during the intercalation / delithiation process, resulting in a decrease in cycle performance, thus limiting the use of pure natural graphite. Application of Ink in Li-ion Batteries
Compared with natural graphite, isotropic graphite anode material has the advantages of good cycle performance, small volume change during intercalation / delithiation, difficult precipitation of metal lithium, and easy balance of the battery. There is a large irreversible capacity loss (>20%), and there is a large voltage hysteresis
Xu Le and others from Changsha University of Science and Technology used self-made phenolic resin as the precursor to coat the surface of isotropic graphite, hoping to improve the electrochemical performance of isotropic graphite, but the effect was not satisfactory

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0010] Embodiment 1: By weight, take 100 parts of isotropic graphite, 8 parts of coating agent coal tar pitch and 50 parts of solvent washing oil, wherein the anisotropy index of isotropic graphite is 1.03, and the average particle diameter D50 is 17.80 μm, the specific surface area is 4.88 m 2 / g, carbon content 99.967%, tap density 1.02 g / cm 3 , Mix and stir them at 220°C, after mixing evenly, vacuumize, remove the solvent, and coat the graphite in the coating agent; first place the obtained product in a debinding furnace, and treat it at 450°C in an inert atmosphere 30 hours; then in an inert atmosphere, carbonize at 1100°C for 12 hours to obtain an isotropic graphite negative electrode material with a carbon layer on the surface; finally, treat at a high temperature for 1 hour under the condition of an inert atmosphere at 2900°C, cool to room temperature, pulverize, and pass through 200 Mesh sieve, that is to obtain the isotropic graphite negative electrode material whose...

Embodiment 2

[0011] Embodiment 2: By weight, take 100 parts of isotropic graphite, 6 parts of coating agent coal tar pitch and 40 parts of solvent xylene, wherein the anisotropy index of isotropic graphite is 1.05, and the average particle diameter D50 is 17.85 μm, the specific surface area is 4.87 m 2 / g, carbon content 99.966%, tap density 1.02 g / cm 3 , Mix and stir them at 100°C, after mixing evenly, vacuumize, remove the solvent, and coat the graphite in the coating agent; first place the obtained product in a debinding furnace, and treat it at 450°C in an inert atmosphere 30 hours; then in an inert atmosphere, carbonize at 1100°C for 13 hours to obtain an isotropic graphite negative electrode material with a carbon layer on the surface; finally, treat at a high temperature for 1 hour under the condition of an inert atmosphere at 2850°C, cool to room temperature, pulverize, and pass through 200 Mesh sieve, that is to obtain the isotropic graphite negative electrode material whose surf...

Embodiment 3

[0012] Embodiment 3: By weight, take 100 parts of isotropic graphite, 10 parts of coating agent coal tar pitch and 30 parts of solvent xylene, wherein the anisotropy index of isotropic graphite is 1.04, and the average particle diameter D50 is 15.42 μm, the specific surface area is 5.22 m 2 / g, carbon content 99.970%, tap density 0.98 g / cm 3 , Mix and stir them at 100°C, after mixing evenly, vacuumize, remove the solvent, and coat the graphite in the coating agent; first place the obtained product in a debinding furnace, and treat it at 450°C in an inert atmosphere 30 hours; then in an inert atmosphere, carbonize at 1100°C for 15 hours to obtain an isotropic graphite negative electrode material with a carbon layer on the surface; finally, treat it at a high temperature of 2650°C in an inert atmosphere for 6 hours, cool to room temperature, pulverize, and pass through 200 Mesh sieve, that is to obtain the isotropic graphite negative electrode material whose surface is coated w...

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Abstract

The invention relates to an isotropic graphite negative electrode material and a preparation method thereof. The negative electrode material is surface-coated artificial graphite prepared by coating and modifying isotropic graphite with a coating agent composed of pitch and / or coal tar The layered isotropic graphite negative electrode material, the weight ratio of the coating agent to the isotropic graphite is 0.03-0.15:1. The preparation method comprises the following steps: weighing 100 parts of isotropic graphite, 3 to 15 parts of coating agent, and 10 to 70 parts of solvent, stirring and mixing evenly at 25 to 350° C., then vacuumizing, removing the solvent, and discharging glue, carbonization, and finally high-temperature treatment under the condition of 2400-3000° C. in an inert protective atmosphere to obtain the negative electrode material. The isotropic graphite negative electrode material has high coulombic efficiency and good cycle performance for the first time. The preparation method is easy to implement industrially.

Description

technical field [0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to an isotropic graphite negative electrode material for a lithium ion battery and a preparation method thereof. Background technique [0002] Natural graphite is widely used as a negative electrode material for lithium-ion batteries, but the compatibility between natural graphite and electrolyte is poor, and the graphite layer is prone to peeling off during the intercalation / delithiation process, resulting in a decrease in cycle performance, thus limiting the use of pure natural graphite. Application of Ink in Li-ion Batteries. Compared with natural graphite, isotropic graphite anode material has the advantages of good cycle performance, small volume change during intercalation / delithiation, difficult precipitation of metal lithium, and easy balance of the battery. There is a large irreversible capacity loss (>20%), and there is a large v...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/1393
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 赵东辉戴涛周鹏伟
Owner SHENZHEN XIANGFENGHUA TECH CO LTD
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