Silicon carbon composite material and preparation method thereof

A technology of silicon-carbon composite materials and carbon layers, which is applied in the direction of nanotechnology, electrical components, electrochemical generators, etc. for materials and surface science, can solve the problems of difficulty in practical application, consumption, and high preparation costs, and achieve improved capacity Effects of performance and cycle life, increased contact area, and high electrochemical capacity

Inactive Publication Date: 2015-12-09
HUBEI UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0005] This type of silicon-based negative electrode material manufacturing process usually has two types of defects: one is that the preparation of a single silicon nanoparticle alleviates the volume expansion effect that occurs when the silicon material itself intercalates and removes lithium to a certain extent, but due to its large specific The surface area and strong surface energy are prone to electrochemical agglomeration during charge and discharge, and

Method used

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  • Silicon carbon composite material and preparation method thereof
  • Silicon carbon composite material and preparation method thereof

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preparation example Construction

[0022] In a second aspect, the present invention provides a method for preparing a silicon-carbon composite material, comprising the following steps:

[0023] A. Mix nano-silica powder with the aqueous turbid solution of carbon source to form a uniform suspension;

[0024] B. The suspension obtained in step A is subjected to spray cracking at 200-700° C. by spray-drying method, and the solvent is removed to obtain a crude product of Si-C composite material, which is then pyrolyzed at 500-900° C. in an inert gas atmosphere. Prepared Si-C porous core-shell composite nanomaterials;

[0025] C. Mix the Si-C porous core-shell composite nanomaterial obtained in step B with a surfactant evenly, add a conductive polymer and an initiator in turn, react at 0-30°C for 4-12 hours, wash and dry to obtain three layers Core-shell structure silicon-carbon composites.

[0026] Preferably, step D is also included. The three-layer core-shell structure silicon-carbon composite material prepared...

Embodiment 1

[0033] First, add 0.10 g of nano-silicon powder particles with a particle size of 100 nm into an aqueous solution of glucose with a concentration of 0.50 M, and ultrasonically disperse for 30 minutes to form a uniform suspension;

[0034] Secondly, the suspension obtained above was sprayed and cracked at 200°C by spray drying method, and then pyrolyzed at 700°C in an inert gas atmosphere to prepare Si-C porous core-shell composite nanomaterials;

[0035] Then, 0.13 g of the above Si-C porous core-shell composite nanomaterial was added to 200 mL of 0.20 mol L -1 In an aqueous solution of cetyltrimethylammonium bromide, ultrasonically disperse for 90 minutes to form a uniform suspension, and then distill 100mL of freshly distilled concentration to 0.40mol L -1 The polypyrrole solution was added dropwise to the suspension, ultrasonicated for 45min, and 20mL of 1.00mol L was slowly added dropwise under stirring. -1 FeCl 3solution, stirred at 5°C for 12 hours, washed with water a...

Embodiment 2

[0038] First, add 0.10 g of nano-silicon powder particles with a particle size of 50 nm into an aqueous solution of maleic acid with a concentration of 0.50 M, and ultrasonically disperse for 30 minutes to form a uniform suspension;

[0039] Secondly, the suspension obtained above is sprayed and cracked at 500°C by spray drying method, and then pyrolyzed at 900°C in an inert gas atmosphere to prepare Si-C porous core-shell composite nanomaterials;

[0040] Then, 0.13 g of the above Si-C porous core-shell composite nanomaterial was added to 200 mL of 1mol L -1 In the aqueous solution of sodium dodecylbenzenesulfonate, ultrasonically disperse for 90min to form a uniform suspension, then distill 100mL freshly to a concentration of 0.20mol L -1 The polypyrrole solution was added dropwise to the suspension, ultrasonicated for 45min, and 20mL of 0.50mol L was slowly added dropwise under stirring. -1 (NH 4 ) 2 S 2 o 8 solution, stirred at 5°C for 12 hours, washed with water and ...

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Abstract

The invention discloses a silicon carbon composite material and a preparation method thereof. According to the preparation method, nano silicon powder particles are taken as a silicon substrate, a Si-C porous shell-core composite material is prepared, and the synergistic effect of silicon and carbon can be fully developed; the silicon material is high in electrochemical capacity, the carbon material is high in conductivity, and the flexible carbon material can be used for absorbing stress and buffering a volume effect of the silicon; meanwhile, the stable and firm shell-core structure can be used for maintaining the material stability; the porous structure can be used for increasing the contact structure of the silicon particles and an electrolyte and improving the compatibility of the silicon particles and the electrolyte; and the three-layer shell-core structure material is dispersed in a graphene material, the conductivity of the material can be further improved, and the capacity performance and the cycle life of an electrode material are improved.

Description

technical field [0001] The invention relates to a lithium battery negative electrode material, in particular to a silicon-carbon composite material and a preparation method thereof. Background technique [0002] Among various new alloyed lithium storage materials, silicon has the highest capacity and can form Li 12 Si 7 , Li 13 Si 4 , Li 7 Si 3 , Li 15 Si 4 and Li 22 Si 5 and other alloys, the theoretical lithium storage capacity is as high as 4212mAh g -1 , more than 10 times the capacity of graphite. Silicon-based negative electrode materials also have the advantages of low reactivity with electrolyte and low lithium intercalation potential. The lithium intercalation voltage platform of silicon is slightly higher than that of graphite, and it is difficult to cause lithium deposition on the surface during charging, and its safety performance is better than that of graphite negative electrode materials. In addition, silicon is one of the most abundant elements in...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M4/62H01M10/0525B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00H01M4/366H01M4/386H01M4/587H01M4/624H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 郭再萍刘建文刘伟冯传启
Owner HUBEI UNIV
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