Preparation method of graphene/graphite lithium ion battery anode material

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as limited wave-absorbing capacity, discontinuity, and reaction temperature limitations, and achieve high specific capacity, cycle stability, and strong Practical technical innovations, the effect of improving the wave absorption

Active Publication Date: 2019-03-01
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, researchers mainly focus on the use of microwave-assisted liquid phase method to reduce graphene oxide, but the quality of reduced graphene oxide (graphene) obtained by this method is not high. This is because the microwave is mainly absorbed by the solvent and the reaction temperature On the other hand, due to the presence of a large number of oxygen-containing functional groups in graphene oxide, its absorbing ability is also limited
In addition, the use of chemical reducing agents in this process usually introduces some difficult-to-remove residues, and its impact on the performance and safety of lithium-ion batteries also brings uncertainty
In addition, with the increase of the reduction degree of graphene oxide, the π-π interaction between the sheets is enhanced, which leads to the agglomeration and stacking of the graphene sheets, forming discontinuous channels, which will hinder the lithium ions in the Rapid diffusion in electrolyte and between electrode particles

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] This example provides the specific preparation steps of a kind of graphene / graphite lithium-ion battery negative electrode material:

[0027] 1) Add 1g of graphite oxide prepared by the Hummers method into 500mL of deionized water, ultrasonicate at 80W, 40KHz for 45min, centrifuge the suspension obtained after ultrasonication at 2500rpm for 45min, remove the unstripped impurities at the bottom after centrifugation, and take the supernatant to obtain oxidation Graphene colloid;

[0028] 2) Mix graphene oxide colloidal solution and polyvinyl alcohol, add graphite and mix evenly, stir and evaporate to dryness, obtain graphene oxide / graphite material, wherein the mass ratio of polyvinyl alcohol and graphene oxide is 1:10, graphite oxide The mass ratio of ene / graphite is 1:5;

[0029] 3) Put the graphene oxide / graphite material into a quartz glass with a lid (with air holes) and put it into an industrial microwave oven to evacuate so that the absolute pressure in the furnac...

Embodiment 2

[0032] This example provides the specific steps of preparing graphene / graphite negative electrode material by the graphene oxide colloid that embodiment 1 makes:

[0033] 1) Mix graphene oxide colloidal solution and ammonium nitrate, add graphite and mix evenly, stir and evaporate to dryness, obtain graphite / graphene oxide material, wherein the mass ratio of ammonium nitrate and graphene oxide is 1:20, graphene oxide / graphene oxide Graphite mass ratio is 1:20;

[0034] 2) Put the graphene oxide / graphite material into a quartz glass with a cover (with air holes) and put it into an industrial microwave oven to evacuate so that the absolute pressure in the furnace is as low as 0.1MPa, and then evacuate after argon gas to normal pressure. Repeat this process three times. Before turning on the microwave, flow argon gas into the reaction chamber to remove the air remaining in the reaction chamber. After heating at 500W for 5 minutes, turn off the microwave and cool to room tempera...

Embodiment 3

[0037] This example provides the specific steps of preparing graphene / graphite negative electrode material by the graphene oxide colloid that embodiment 1 makes:

[0038] 1) Mix graphene oxide colloidal solution and ammonium nitrate, then add graphite and mix evenly, stir and evaporate to dryness, obtain graphene oxide / graphite material, wherein the mass ratio of ammonium nitrate and graphene oxide is 1:15, graphene oxide / graphene oxide The mass ratio of graphite is 1:10;

[0039] 2) Put the graphene oxide / graphite material into a quartz glass with a cover (with air holes) and put it into an industrial microwave oven to evacuate so that the absolute pressure in the furnace is as low as 0.1MPa, and then evacuate after argon gas to normal pressure. Repeat this process three times. Before turning on the microwave, flow argon gas into the reaction chamber to remove the air remaining in the reaction chamber. After heating with 2500W microwave for 1s, turn off the microwave and co...

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Abstract

The invention provides a preparation method of a graphene/graphite lithium ion battery anode material. The preparation method is characterized by comprising the following steps: (1) adding graphite oxide into deionized water, and performing ultrasonic treatment for 20-60 min; centrifuging obtained suspension for 20-60 min at the condition of 1,500-3,000 rpm; after the centrifugation, removing supernatant with impurities not stripped at the bottom to obtain graphene oxide colloid; (2) mixing a graphene oxide colloid solution obtained in the step (1) with an expanding agent, adding a graphite electrode material, and stirring and drying to obtain a graphene oxide/graphite material; (3) performing microwave heating on the graphene oxide/graphite material obtained in the step (2) in an inert atmosphere to obtain the graphene/graphite lithium ion battery anode material. The preparation method provided by the invention has the advantages of simple technology, short path and low cost; the obtained lithium battery anode material has great specific capacity and high cyclic stability.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a preparation method of a graphene / graphite lithium ion battery negative electrode material. Background technique [0002] Since the commercial application of lithium-ion batteries in the early 1990s, it has been widely used in portable electronic devices such as mobile phones, notebook computers, digital cameras, etc., and has been widely used in electric vehicles, hybrid vehicles, military and Aerospace and other fields have been further applied. In recent years, in order to solve the problem of oil shortage and actively improve the air pollution situation, my country has taken the development of new energy vehicles as a major measure of strategic industries, and the demand for lithium-ion batteries will continue to grow in the future. [0003] Among the various components of lithium-ion batteries, the electrode material is the key and core, which directly determines the b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/587H01M10/0525
CPCH01M4/364H01M4/587H01M10/0525Y02E60/10
Inventor 金双玲唐珊古飞蛟吴家辉魏旭东顾雪婷樊佳琪金鸣林张睿刘艳王占勇
Owner SHANGHAI INST OF TECH
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