Method for modifying natural graphite

A natural graphite, modified technology, applied in the direction of electrical components, battery electrodes, circuits, etc., can solve the problems of low charge and discharge efficiency and poor cycle performance of natural graphite, achieve improved electrochemical performance, high charge and discharge efficiency, reduce common embedded effect

Inactive Publication Date: 2013-02-13
无锡东恒新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This leads to problems such as low charge and discharge e

Method used

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  • Method for modifying natural graphite
  • Method for modifying natural graphite
  • Method for modifying natural graphite

Examples

Experimental program
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Embodiment 1

[0036] The modified natural graphite material for lithium-ion batteries in this example uses concentrated sulfuric acid to oxidize spherical natural graphite at 200°C for 10 hours, and then uses thermosetting phenolic resin to modify it. The solvent for dissolving the phenolic resin is Water ethanol, phenolic resin coating amount is 10%.

[0037] The preparation process is as follows: put 100g of spherical natural graphite (particle size D50 is 17.8μm) in a reaction kettle and react with 250ml of concentrated sulfuric acid with a concentration of 98% at 200°C for 10 hours; the reacted natural graphite balls are centrifuged and washed repeatedly, Dry last. Weigh 10 g of thermosetting phenolic resin and add it to ethanol to dissolve; add oxidized natural graphite balls to ethanol dissolved in phenolic resin, stir for 4 hours to make the solution uniform, and let it stand for 1 hour. At 70°C, evaporate the ethanol to dryness and pass through a 300-mesh sieve. Put the sieved gra...

Embodiment 2

[0043] Put 100g of spherical natural graphite (average particle size of 10μm) in a reaction kettle and react with 200ml of 30% hydrogen peroxide at 50°C for 25 hours; the reacted natural graphite balls are centrifuged repeatedly, rinsed, and finally dried. Weigh 100 g of polystyrene and add it into acetone to dissolve; add the oxidized natural graphite ball into the acetone dissolved in polystyrene, stir for 4 hours to make the solution uniform, and let it stand for 1 hour. At 70°C, evaporate acetone to dryness and pass through a 300-mesh sieve. Put the sieved graphite into the quartz boat, put it into the quartz tube, push the tube furnace, and control the heating rate of the system with the program temperature controller. Access to N 2 As a protective gas to prevent graphite from being oxidized by air, raise the temperature to 100°C at a rate of 5°C / min, keep it for 12 hours, then raise it to 700°C at a rate of 3°C / min, keep it for 24 hours, and keep it at 5°C / min cooling...

Embodiment 3

[0045] Put 100g of spherical natural graphite (average particle size of 30μm) in a reaction kettle and react with ammonium persulfate with a concentration of 1mol / L at 100°C for 15 hours; the reacted natural graphite balls are centrifuged repeatedly, rinsed, and finally dried. Weigh 500g of polyvinyl alcohol and add it into cyclohexane to dissolve; add the oxidized natural graphite ball into cyclohexane dissolved in polyvinyl alcohol, stir for 4h to make the solution uniform, and let it stand for 1h. At 70°C, evaporate the cyclohexane to dryness and pass through a 300-mesh sieve. Put the sieved graphite into the quartz boat, put it into the quartz tube, push the tube furnace, and control the heating rate of the system with the program temperature controller. Access to N 2 As a protective gas to prevent graphite from being oxidized by air, heat up to 600°C at a rate of 30°C / min, hold for 0.2 hours, then raise to 1500°C at a rate of 20°C / min, hold for 1 hour, and heat at 20°C ...

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Abstract

The invention discloses a method for modifying natural graphite. The method comprises the steps of: (1) using oxidizing acid or salt to carry out oxidation treatment on the natural graphite to obtain an intermediate product graphite A; (2) centrifuging, washing and drying the graphite A to obtain an immediate product graphite B; (3) dissolving a polymer which is used as a shell material into an organic solvent to obtain a polymer solution; (4) adding the graphite B into the polymer solution, stirring the mixture, thus uniformly soaking the graphite B into the polymer solution, stewing the mixture, and evaporating an organic solvent, sieving the mixture to obtain graphite C; (5) curing the graphite C for 0.2-12 hours at 100 DEG C to 600 DEG C under the protective atmosphere to obtain graphite D; (6) carbonizing the graphite D for 1-24 hours at 700 DEG C to 1500 DEG C to finally obtain the modified graphite to be prepared in the invention. According to the method disclosed by the invention, the process is simple, the control is easy, the price is low, and the industrial application is facilitated.

Description

technical field [0001] The invention relates to a preparation method of a negative electrode material for a lithium ion secondary battery, in particular to a preparation method of modified natural graphite. Background technique [0002] In the 1990s, Japan's Sony Energy Technology Company took the lead in successfully developing lithium-ion batteries using carbon negative electrodes, and lithium-ion batteries have rapidly occupied the civilian secondary battery market at an average annual rate of 15%. In recent years, with the rapid development of mobile communications and the popularization of notebook computers, lithium-ion batteries have rapidly replaced nickel-cadmium and nickel-metal hydride batteries, becoming the most popular high-energy batteries, and have shown great promise in fields such as electric vehicles and energy storage. Eye-catching development prospects. [0003] The rapid development of lithium-ion batteries is mainly due to the contribution of electrod...

Claims

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Application Information

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IPC IPC(8): H01M4/583
CPCY02E60/12Y02E60/10
Inventor 沈宇栋余爱水黄桃高文超姚熠
Owner 无锡东恒新能源科技有限公司
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