Preparation method and application of carbon-coated graphene composite material for lithium ion battery

A composite material, graphene technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of fast capacity decay, low irreversible capacity loss, and graphene specific surface, etc. Easy-to-control, easy-to-use effects

Inactive Publication Date: 2013-03-13
SUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, a single graphene material is used as an electrode material, which is limited by many factors, such as the specific surface of graphene is too large (theoretical value 2630m 2 / g), and the sheets are easy to agglomerate, which greatly improves the It reduces the irreversible capacity loss (lower first Coulombic efficiency (<73%)) and reduces its conductivity as an electrode material, which has a negative impact on the electrode fabrication process
In particular, the capacity of a single graphene electrode material decays too quickly when charging and discharging at a high rate

Method used

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  • Preparation method and application of carbon-coated graphene composite material for lithium ion battery
  • Preparation method and application of carbon-coated graphene composite material for lithium ion battery
  • Preparation method and application of carbon-coated graphene composite material for lithium ion battery

Examples

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Embodiment 1

[0030] (1) The preparation method of raw material graphene oxide: the improved Hummers method is used to prepare graphite oxide, specifically: slowly add 1g of graphite into a round bottom flask containing 35ml of 98% sulfuric acid under stirring, and then add 0.5g of sodium nitrate , the temperature was maintained at 0° C., and stirred rapidly for 2 hours. Slowly add 5g of potassium permanganate (temperature controlled below 20°C), it turns dark green, remove the ice water bath after adding potassium permanganate, control the temperature at (35±3)°C, keep stirring for 2 hours, slowly add 100ml of distilled water (The temperature rose to 98°C), stirred rapidly at this temperature for 2.5h, and then stirred slowly for 15h. The product was first treated with 30% H 2 O 2 Wash with aqueous solution, then wash with 5% hydrochloric acid solution, and wash with deionized water until there is no SO in the filtrate 4 2- (BaCl 2 No white precipitate was detected)...

Embodiment 2

[0034] The preparation method of this embodiment is the same as that of Example 1, wherein the mass of graphite oxide and the volume ratio of aniline monomer in step (2) are adjusted to 1:2, and the concentration of ammonium persulfate increases according to a certain amount along with the increase of the amount of aniline monomer. The corresponding increase of the ratio, under other conditions unchanged, also obtains a black product, that is, obtains carbon-coated graphene.

Embodiment 3

[0036] (1) The preparation method of the raw material graphene oxide: the same as in Example 1 (1).

[0037] (2) The preparation method of polypyrrole-coated graphene oxide: disperse 0.5g graphite oxide in 1M hydrochloric acid solution, ultrasonically disperse for 30min to form a stable graphene oxide solution; add 0.5ml pyrrole monomer into the solution, and continue Stir, then slowly drop 11.5g / L ammonium persulfate solution into the above solution, and keep the polymerization reaction at 0-4°C for 4-6h. The obtained polypyrrole-coated graphite oxide was repeatedly washed alternately with ethanol and deionized water for 3-4 times, and vacuum-dried at 60° C. for more than 12 hours to obtain a product, that is, polypyrrole-coated graphene oxide.

[0038] (3) Carbonization of polypyrrole-coated graphene oxide: Grind the polypyrrole-coated graphene oxide obtained in (2), put it into a porcelain boat, place it in the middle heating area of ​​a tube furnace, and feed it with...

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Abstract

The invention discloses a preparation method and an application of a carbon-coated graphene composite material for a lithium ion battery. The preparation method comprises the steps of: dispersing graphite oxide or graphene in a diluted acid solution, adding different amount of polymer monomers in the solution, continuously stirring the solution, slowly adding a polymer initiator for generating polymerization reaction, coating the graphite oxide or the graphene by a polymer generated through the polymerization reaction of deionized water and ethanol, and carrying out vacuum drying after alternate cleaning for multiple times; and grinding the graphite oxide or the graphene coated by the polymer, then placing the ground graphite oxide or graphene in flowing protective gas to heat for generating high temperature thermal reduction and carbonization reaction, and at last cooling the ground graphite oxide or graphene to be at room temperature in the flowing protective gas, so as to obtain the carbon-coated graphene material. The prepared carbon-coated graphene material has the advantages of high rate and long service life; for the present single graphene electrode material, the preparation technological problems caused by the overlarge specific surface, fast capacity fading problem caused by high rate, and the like are solved; and the carbon-coated graphene composite material can be adopted as a negative electrode material of the lithium ion battery.

Description

Technical field [0001] The present invention involves the field of new energy materials and electrochemical research, and specifically involves a graphene composite material preparation method and its application. Background technique [0002] Recently, complex materials such as metal oxides / carbon, conductive polymer / carbon, metal nitride, metal nitride, etc. have been widely used for research.Nuclear / shell material composite refers to the coated or inorganic material of the single layer or multi -layer of organic or inorganic materials. This is an effective way to improve the stability and surface chemical performance of the nuclear particles, and it can achieve impossible impossibleThe unique physical and chemical characteristics obtained from one material.The excellent performance of nuclear / shell materials is related to their unique structure. The performance of nuclear particles has improved significantly with the changes in the shell around the nuclear particles.The charac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583
CPCY02E60/12Y02E60/10
Inventor 王海波朱碧玉高立军
Owner SUZHOU UNIV
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