Preparation method of composite negative electrode material for lithium ion battery

A technology for lithium ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as hindering practical application, prone to separation, poor bonding strength, etc., to improve cycle stability and excellent electrochemical performance. , the effect of enhancing structural stability

Active Publication Date: 2015-10-21
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002]Si anode has the highest theoretical specific capacity (4 200 mAh·g-1), low lithium extraction potential (0.02~0.6 V vs. Li+/Li), has received extensive attention from scholars at home and abroad; however, the huge volume change (~300%) of the material itself during the delithiation/intercalation process will cause the electrode material to gradually powder. The electrical contact between the silicon particles and the current collector is deteriorated, causing the specific capacity of the material to decay rapidly, and the poor rate performance accompanied by the lower electronic conductivity further hinders the use of silicon as a material. The practical application of lithium-ion battery negative electrode materials; and graphene because of its excellent physical and chemical properties, such as excellent electronic conductivity and high specific surface area, and its structural flexibility can help buffer other material

Method used

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  • Preparation method of composite negative electrode material for lithium ion battery
  • Preparation method of composite negative electrode material for lithium ion battery
  • Preparation method of composite negative electrode material for lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Using nano-silicon as raw material, in the ethanol solution of water, choose cetyltrimethylammonium bromide (CTAB) as dispersant, triethanolamine as reagent A, control m (nano-silicon) : m (water) : m(CTAB) : m (Reagent A) : m (absolute ethanol) =2 : 2 : 0.2 : 5 : 25, the reaction temperature is 25 ℃, the reaction time is 24 h, after centrifugation, the m - Si powder.

[0025] Will m -Si and graphite oxide according to 1 : 4 ratio to disperse, add polyvinylpyrrolidone (the addition ratio is 1 times the theoretical amount) as the reducing agent, ultrasonically stir and disperse evenly, then transfer it to a hydrothermal reaction kettle for hydrothermal reaction, the reaction temperature is 160 ℃, and the reaction time is After 20 h, the obtained product was filtered and placed in aqueous solution for ion exchange for 24 h, washed and freeze-dried for 48 h to obtain m -SiG composite anode material.

[0026] The SEM image of the obtained composite material is as...

Embodiment 2

[0031] Using nano-silicon as the raw material, in the ethanol solution of water, choose sodium dodecylbenzenesulfonate (SDBS) as the dispersant, the mixture of sulfuric acid and hydrogen peroxide as the reagent A, and control m (nano-silicon) : m (water) : m(SDBS) : m (Reagent A) : m(absolute ethanol) =1 : 2 : 0.5 : 8 : 25, the reaction temperature is 25 ℃, the reaction time is 24 h, after centrifugation, the m - Si powder.

[0032] Will m -Si and graphite oxide according to 1 : 2 ratio to disperse, add ethylene glycol (the addition ratio is 1.5 times of the theoretical amount) as the reducing agent, ultrasonically stir and disperse evenly, then transfer to the hydrothermal reaction kettle for hydrothermal reaction, the reaction temperature is 180 ℃, and the reaction time is After 8 h, the obtained product was filtered and placed in aqueous solution for ion exchange for 48 h, washed and freeze-dried for 60 h, and its first-time delithiation specific capacity was as hi...

Embodiment 3

[0034] Using nano-silicon as raw material, in the ethanol solution of water, choose cetyltrimethylammonium bromide (CTAB) as dispersant, triethanolamine as reagent A, control m (nano-silicon) : m (water) : m(CTAB) : m(A) : m (absolute ethanol) =2 : 2 : 0.2 : 5 : 25, the reaction temperature is 25 ℃, the reaction time is 24 h, after centrifugation, the m - Si powder.

[0035] Will m -Si and graphite oxide according to 1 : 1 ratio for dispersion, adding polyethylene glycol (the addition ratio is 3 times the theoretical amount) as a reducing agent, ultrasonically stirred and dispersed evenly, then transferred to a hydrothermal reaction kettle for hydrothermal reaction, the reaction temperature is 250 ℃, and the reaction time After 4 hours, the obtained product was filtered and placed in aqueous solution for ion exchange for 72 hours, washed and freeze-dried for 72 hours, and its first-time delithiation specific capacity was as high as 1476.8 mAh / g.

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Abstract

The invention discloses a preparation method of a composite negative electrode material for a lithium ion battery. The method is characterized in that the m-Si@G composite negative electrode material is prepared through the combination of a surface modification method and a hydrothermal reduction method. The method specifically includes the following steps of firstly, conducting surface modification on nanometer silicon, adding the nanometer silicon together with a reducing agent to dispersion liquid of graphite oxide, conducting hydrothermal reaction after dispersion is uniform, shifting into a water solution to conduct ion exchange after suction filtration is conducted, and obtaining the composite negative electrode material after suction filtration and freeze drying are conducted. The prepared m-Si@G composite negative electrode material is stable in structure and excellent in circulating performance and rate capability.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials and preparation methods thereof, and relates to a lithium ion battery m -The preparation method of SiG composite anode material. Background technique [0002] Silicon anode has the highest theoretical specific capacity (4 200 mAh g -1 ), low lithium extraction potential (0.02~0.6 V vs. Li + / Li), has received extensive attention from scholars at home and abroad; however, the huge volume change (~300%) of the material itself during the delithiation / intercalation process will cause the electrode material to gradually pulverize and break, making the silicon particles and their contact with each other The electrical contact between the current collectors becomes poor, causing the specific capacity of the material to decay rapidly, and the poor rate performance accompanied by the lower electronic conductivity further hinders the practical application of silicon as a negative electrode mat...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 苏明如刘云建窦爱春张志强王起亮
Owner JIANGSU UNIV
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