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Silicon composite negative electrode material, preparation method and lithium ion battery

A negative electrode material and conductive network technology, applied in the field of batteries, can solve the problems of poor strength, no bonding effect, and poor bonding effect of conductive carbon materials, and achieve the effects of improving compatibility, avoiding direct contact, and enhancing structural strength

Inactive Publication Date: 2019-05-03
SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the inherent volume change of silicon during the cycle always exists, and the inactive components (binder, conductive agent) in the electrode material greatly affect the integrity of the entire electrode, and the traditional binder itself is sticky. The junction effect is poor, non-conductive, the strength of the conductive carbon material is poor, and there is no combination between silicon nanoparticles, binders, and conductive agents, and it becomes an isolated system

Method used

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  • Silicon composite negative electrode material, preparation method and lithium ion battery
  • Silicon composite negative electrode material, preparation method and lithium ion battery
  • Silicon composite negative electrode material, preparation method and lithium ion battery

Examples

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preparation example Construction

[0040] refer to figure 1 , the present invention also discloses a preparation method of the silicon composite negative electrode material, the preparation method comprising the following steps:

[0041] Step S1, performing hydroxylation treatment on the surface of silicon nanoparticles to obtain hydroxylated silicon nanoparticles;

[0042] Step S2, coating the surface of the hydroxylated silicon nanoparticles with a conductive polymer;

[0043] Step S3, partially reducing graphene oxide to prepare reduced graphene oxide;

[0044] Step S4, mixing and reacting the silicon nanoparticles whose surface is coated with the conductive polymer and the reduced graphene oxide to obtain a silicon composite negative electrode material.

[0045] In step S1, the silicon nanoparticles are hydroxylated by an oxidation method. More specifically, a strong acid is mixed with a first oxidizing agent to obtain an oxidizing agent solution, silicon nanoparticles are added to the oxidizing agent so...

Embodiment 1

[0057] 15ml of concentrated sulfuric acid and 5ml of 30% H 2 o 2 The solution was slowly mixed, and 100 mg of silicon nanoparticles were added to the above solution, and then stirred at room temperature for 24 hours. After the reaction was completed, suction filtration was repeated, and deionized water was washed until neutral to obtain hydroxylated silicon nanoparticles; 100 mg of the hydroxyl Silica nanoparticles were dispersed in 10mL deionized water, 10mg EDOT monomer and 45mg PSS were added, and after stirring for 20 minutes, 20mg Na 2 S 2 o 8 , followed by the addition of 0.015 mg FeCl 3 As a polymerization reaction catalyst, react at room temperature and magnetic stirring for 12 hours, and the resulting mixed solution is further purified by ion exchange resin and suction filter to obtain silicon nanoparticles coated with conductive polymer in situ; after preparing graphene oxide by Hummers method, Get 1g of said graphite oxide and disperse it in 100mL of deionized w...

Embodiment 2

[0059] The difference from Example 1 is: the volume of the 55% hydroiodic acid added in this example is 25mL.

[0060] Other steps are the same as in Example 1 and will not be repeated here.

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Abstract

The invention provides a silicon composite negative electrode material, which comprises silicon nanoparticles, a conductive polymer and reduced graphene oxides, wherein the conductive polymer is bonded on and coats the surfaces of the silicon nanoparticles, the reduced graphene oxides are stacked to form a three-dimensional conductive network framework, and the silicon nanoparticles coated with the conductive polymer are bonded and dispersed in the conductive network framework. The invention further discloses a preparation method of the silicon composite negative electrode material. The preparation method comprises the steps of: performing surface hydroxylation processing on the silicon nanoparticles to obtain hydroxylated silicon nanoparticles; coating the hydroxylated silicon nanoparticles with the conductive polymer; partially reducing graphene oxides to prepare reduced graphene oxides; and mixing the silicon nanoparticles coated with the conductive polymer with the reduced grapheneoxides for reaction to obtain the silicon composite negative electrode material.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a silicon composite negative electrode material, a preparation method and a lithium ion battery. Background technique [0002] The current commercial anode material is graphite, which has the advantages of stable cycle performance, long cycle times, abundant resources, and more importantly, low cost. Although the graphite negative electrode has many advantages, its theoretical specific capacity is only 372mAh / g. In addition, because the lithium intercalation potential of graphite is very close to the deposition potential of lithium metal, lithium dendrites are easily formed on the electrode surface, making lithium-ion batteries failure or even an explosion hazard. [0003] Compared with graphite-based negative electrode materials, the theoretical specific capacity of silicon materials with a higher content in the earth's crust is the highest among the currently studied negative electrod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCY02E60/10
Inventor 吕伟祁少伟黄志佳杨全红康飞宇
Owner SHENZHEN GRADUATE SCHOOL TSINGHUA UNIV