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Preparation method for modified graphene and application of modified graphene to positive materials for lithium batteries

A graphene and modification technology, applied in the direction of active material electrodes, positive electrodes, battery electrodes, etc., can solve the problems of easy agglomeration of graphene, deterioration of graphene dispersion performance, increase of graphene layer thickness, etc., and achieve good dispersion. , The effect of increasing the electric capacity and charging and discharging rate, and adding less amount

Inactive Publication Date: 2015-06-17
山东利特纳米技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, graphene is easy to agglomerate, resulting in poor dispersion of graphene in solvents, irreversible agglomeration, and increased graphene layer thickness.

Method used

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  • Preparation method for modified graphene and application of modified graphene to positive materials for lithium batteries
  • Preparation method for modified graphene and application of modified graphene to positive materials for lithium batteries
  • Preparation method for modified graphene and application of modified graphene to positive materials for lithium batteries

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Preparation of modified graphene:

[0032] (1) Graphene oxide slurry is obtained by reacting natural flake graphite with strong oxidant potassium permanganate and 98% concentrated sulfuric acid;

[0033] (2) Weigh the graphene oxide slurry prepared above, wash with distilled water until neutral and dry;

[0034] (3) Reduce the dried graphene oxide at 400°C under the protection of nitrogen to obtain graphene;

[0035] (4) Ultrasound the graphene in hydrogen peroxide solution with 30% oxidant for 2 hours, the proportion of graphene and hydrogen peroxide solution is 1g / L, take it out, wash and dry it;

[0036] (5) Prepare cetyltrimethylammonium bromide with a concentration of 0.5mg / mL;

[0037] (6) Add graphene to cetyltrimethylammonium bromide solution according to the mass ratio of graphene and cetyltrimethylammonium bromide as 1:5, after ultrasonication, suction filtration, vacuum at 60°C drying to obtain the sample;

[0038] (7) Measure its powder resistivity to be...

Embodiment 2

[0041] Preparation of modified graphene:

[0042] (1) Graphene oxide slurry is obtained by reacting natural flake graphite with strong oxidant potassium permanganate and 98% concentrated sulfuric acid;

[0043] (2) Weigh the graphene oxide slurry prepared above, wash with distilled water until neutral and dry;

[0044] (3) Reduce the dried graphene oxide at 600°C under the protection of nitrogen to obtain graphene;

[0045] (4) Ultrasound the graphene in hydrogen peroxide solution with 30% oxidant for 3 hours, the proportion of graphene and hydrogen peroxide solution is 3g / L, take it out, wash and dry it;

[0046] (5) Prepare octadecyltrimethylammonium chloride with a concentration of 0.5mg / mL;

[0047] (6) Add graphene to octadecyltrimethylammonium chloride solution according to the mass ratio of graphene and octadecyltrimethylammonium chloride of 2:5, after ultrasonication, suction filtration, vacuum at 60°C drying to obtain the sample;

[0048] (7) Measure its powder re...

Embodiment 3

[0051] Preparation of modified graphene:

[0052] (1) Graphene oxide slurry is obtained by reacting natural flake graphite with strong oxidant potassium permanganate and 98% concentrated sulfuric acid;

[0053] (2) Weigh the graphene oxide slurry prepared above, wash with distilled water until neutral and dry;

[0054] (3) Reduce the dried graphene oxide at 800°C under the protection of nitrogen to obtain graphene;

[0055] (4) Ultrasound the graphene in oxidant 10% nitric acid solution for 4 hours, the proportion of graphene and nitric acid solution is 8g / L, take it out, wash and dry;

[0056] (5) Prepare tetradecyltrimethylammonium chloride with a concentration of 0.5mg / mL;

[0057] (6) Add graphene to tetradecyltrimethylammonium chloride solution according to the mass ratio of graphene and tetradecyltrimethylammonium chloride at 2:1, after ultrasonication, suction filtration, vacuum at 60°C drying to obtain the sample;

[0058] (7) Measure its powder resistivity to be 1...

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Abstract

The invention discloses a preparation method of modified graphene and application of the modified graphene to positive materials for lithium batteries. The preparation method for the modified graphene comprises the following steps: preparing a graphene oxide slurry; reducing the graphene oxide slurry at high temperature to prepare graphene; modifying the graphene by a graphene oxidant; modifying the graphene by quaternary ammonium salt; doping the modified graphene into the positive materials for the lithium batteries. The modified graphene prepared by the method has the advantages that the modified graphene is free of agglomeration, excellent in dispersion in solvents, free of toxicity in preparation process, free of pollution to environment and long in service life; through the application of the modified graphene to the positive materials for the lithium batteries, the electric capacity and the charge-discharge rate of the batteries are improved obviously; a small amount of modified graphene is added, so that the cost is reduced.

Description

technical field [0001] The invention specifically relates to a preparation method of modified graphene and its application in lithium battery cathode materials. Background technique [0002] As a lithium-ion battery cathode material, lithium iron phosphate has a relatively high theoretical specific capacity of 170mAh / g, good thermal and chemical stability, low cost, low toxicity and good safety performance, and long cycle life Etc. However, due to the defects of low electrical conductivity and low lithium ion conductivity of lithium iron phosphate, the low temperature performance and rate discharge performance of the battery are poor. [0003] Graphene itself is prepared from graphite, but its theoretical specific capacity is twice that of graphite (graphite 372mAhg-1, graphene 744 mAhg -1 ). Graphene itself is very thin, wrapping other compounds to form a compound, which can further enhance the reversibility of the charge and discharge reaction of lithium batteries, and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583H01M10/0525
CPCH01M4/131H01M4/133H01M4/1391H01M4/1393H01M4/364H01M4/505H01M4/583H01M10/0525H01M2004/028Y02E60/10
Inventor 王圆圆宋肖肖孙明娟
Owner 山东利特纳米技术有限公司
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