Preparation method of silicon-carbon negative electrode material of lithium ion battery

A lithium-ion battery, silicon carbon technology, applied in the direction of battery electrodes, secondary batteries, circuits, etc., can solve the problems of side reactions between nano-silicon particles and electrolyte, battery discharge capacity and cycle capacity reduction, etc., to avoid side reactions, Effect of improving cycle efficiency

Inactive Publication Date: 2019-05-03
江西中汽瑞华新能源科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing a silicon-carbon negative electrode of a lithium-ion battery, which uniformly coats nano-silicon particles with graphene and Ketjen black, avoids side reactions between the silicon negative electrode and the electrolyte, and i...

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  • Preparation method of silicon-carbon negative electrode material of lithium ion battery
  • Preparation method of silicon-carbon negative electrode material of lithium ion battery
  • Preparation method of silicon-carbon negative electrode material of lithium ion battery

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Embodiment 1

[0030] A method for preparing a silicon-carbon negative electrode material for a lithium-ion battery, the specific preparation steps are as follows:

[0031] In the first step, 1g of nano-Si powder with an average particle size of 100nm, 0.1g of polyethylene glycol p-isooctylphenyl ether, and 0.5g of glucose were added to 50g of absolute ethanol, and after ultrasonic stirring for 45min, a uniformly dispersed Nano-Si suspension; 2g graphene and 1g Ketjen black were added to 50g absolute ethanol, and a uniformly dispersed graphene / Ketjen black mixture was formed after acoustic stirring for 45min;

[0032] In the second step, the graphene / Ketjen Black mixed solution is slowly and uniformly added to the mixed solution containing nano-silicon powder, and after being ultrasonically stirred for 30 minutes, a uniformly dispersed silicon and graphene / Ketjen Black composite material precursor is mixed solution;

[0033] In the third step, the precursor solution obtained in the se...

Embodiment 2

[0036] In the first step, 1g of nano-Si powder with an average particle size of 150nm, 0.05g of cetyltrimethylammonium bromide, and 0.33g of sucrose were added to 50g of absolute ethanol, and a uniformly dispersed nano-Si suspension was formed after ultrasonic stirring for 40min. Liquid; 1.5g graphene and 0.5g Ketjen black are joined in 50g dehydrated alcohol, form the graphene / ketjen black mixed solution of uniform dispersion after acoustic stirring 40min;

[0037] In the second step, the graphene / Ketjen Black mixed solution is slowly and uniformly added to the mixed solution containing nano-silicon powder, and after being ultrasonically stirred for 45 minutes, a uniformly dispersed silicon and graphene / Ketjen Black composite material precursor is mixed solution;

[0038] In the third step, the precursor solution obtained in the second step is fully dried with dry powder making equipment, and then the obtained powder particles are placed in a tube furnace with an argon ...

Embodiment 3

[0041]In the first step, 1g of nano-Si powder with an average particle diameter of 200nm, 0.08g of sodium tripolyphosphate, and 0.25g of citric acid are added to 50g of absolute ethanol, and a uniformly dispersed nano-Si suspension is formed after ultrasonic stirring for 35min; Add 1.25g of graphene and 1.25g of Ketjen black into 50g of absolute ethanol, and form a uniformly dispersed graphene / Ketjen black mixture after acoustic stirring for 35 minutes;

[0042] In the second step, the graphene / Ketjen Black mixed solution is slowly and uniformly added to the mixed solution containing nano-silicon powder, and after being ultrasonically stirred for 50 minutes, a uniformly dispersed silicon and graphene / Ketjen Black composite material precursor is mixed solution;

[0043] The third step is to fully dry the precursor solution obtained in the second step with dry powder making equipment, and then place the obtained powder particles in a tube furnace with a nitrogen gas flow r...

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Abstract

The invention discloses a preparation method of a silicon-carbon negative electrode of a lithium ion battery. The preparation method comprises the following steps: weighing a proper amount of nano silicon powder, a dispersing agent and an organic carbon source, and dispersing the nano silicon powder, the dispersing agent and the organic carbon source in absolute ethyl alcohol to obtain mixed solution; adding graphene and Ketjen black into absolute ethyl alcohol to obtain mixed solution after dispersing; dispersing the two types of mixed solution to obtain precursor mixed solution; fully dryingthe obtained precursor solution to obtain powder particles, and carrying out high-temperature carbonization on the powder particles to obtain a silicon-carbon composite material; and uniformly mixingthe obtained silicon-carbon composite material with other carbon materials according to a certain ratio to obtain the silicon-carbon negative electrode material of the lithium ion battery. Accordingto the invention, the nano silicon particles are uniformly coated by graphene and Ketjen black, thereby avoiding the side reaction between the silicon negative electrode and the electrolyte, improvingthe cycle efficiency of the lithium battery, and solving the problem that the discharge capacity and the cycle capacity of the battery are reduced due to the side reaction between nano silicon particles and the electrolyte caused by direct mixing of graphene by the negative electrode material of the existing lithium battery.

Description

technical field [0001] The invention belongs to the technical field, and relates to a method for preparing a silicon-carbon negative electrode material for a lithium-ion battery. Background technique [0002] With the rapid development of human society, the energy density of traditional lithium-ion batteries has been difficult to meet people's needs, especially in the field of electric vehicles. Therefore, there is an urgent need to develop lithium-ion batteries with higher energy density to meet market demand. [0003] At present, the theoretical specific capacity of the commercialized graphite negative electrode is 372mAh / g, which is relatively low. It is difficult to match the positive electrode materials with high specific capacity (high-nickel ternary materials, lithium-rich materials, etc.), which greatly limits lithium-ion batteries. Increased overall energy density. However, the silicon negative electrode has a theoretical specific capacity as high as 4200mAh / g, an...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCY02E60/10
Inventor 张小溪陈伟王海文范进雷
Owner 江西中汽瑞华新能源科技有限公司
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