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A silicon negative electrode material and a negative electrode sheet coated with carbon nanotubes, a preparation method thereof and a lithium ion battery

A technology of carbon nanotubes and negative electrode materials, applied in the direction of negative electrodes, battery electrodes, secondary batteries, etc., can solve problems such as poor cycle performance, uneven distribution of carbon nanotubes, detachment, etc., achieve stable electrochemical performance, and facilitate large-scale production The effect of large-scale production and simple preparation process

Inactive Publication Date: 2019-01-04
厦门高容新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, silicon anode materials also have the following problems: 1. The huge volume effect produced by silicon during the charge-discharge cycle can easily cause the pulverization of the material, and then separate from the current collector, resulting in a rapid decline in capacity and poor cycle performance; 2. Silicon itself is a semiconductor material, and its conductivity needs to be improved, so it needs to be doped with highly conductive substances; 3. During circulation, silicon will react with lithium hexafluorophosphate in the electrolyte, and it is difficult to form a stable SEI film, making the capacity retention rate and Coulombic inefficiency
Vapor deposition (CVD) has the advantages of low reaction temperature, simple equipment, and easy control of the reaction. However, due to the uneven distribution of carbon transported in the gas phase on the sample, the grown carbon nanotubes will appear unevenly distributed, making the sample The consistency is affected; moreover, this method requires the use of H 2 、CH 4 Inflammable and explosive gases, such as experimental safety hazards are worrying

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  • A silicon negative electrode material and a negative electrode sheet coated with carbon nanotubes, a preparation method thereof and a lithium ion battery
  • A silicon negative electrode material and a negative electrode sheet coated with carbon nanotubes, a preparation method thereof and a lithium ion battery

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preparation example Construction

[0033] The present invention also provides a method for preparing a negative electrode sheet. The method comprises uniformly mixing the negative electrode material with a conductive agent, a binder and a solvent to obtain an electrode slurry, and coating the electrode slurry on the surface of a current collector, and drying Dry, wherein, the negative electrode material is the silicon negative electrode material covered with carbon nanotubes.

[0034] The main improvement of the preparation method of the negative electrode sheet provided by the present invention is to adopt a new negative electrode material, and the specific types of conductive agent, binder and solvent and their consumption with the negative electrode material and the like can be compared with the existing ones. The technique is the same. For example, specific examples of the conductive agent include, but are not limited to: at least one of super carbon black, graphene, carbon fiber and graphite. Specific exa...

Embodiment 1

[0041] Weigh 14g PEG (M W :1000) and 50g CA (C 6 h 8 o 7 ·H 2 (0), add 150ml dehydrated alcohol (95%), after magnetic stirring is to dissolving, then add 25g cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O), magnetically stirred for 50min to obtain a precursor solution. Add 50 g of nano-silicon (0.01-10 μm in particle size) to the precursor solution, stir magnetically for 2.5 hours, and filter the resulting slurry several times (washing with deionized water three times first, and finally with ethanol Washed twice, the same below), placed in a vacuum drying oven, dried at 60° C. for 5 hours to obtain a precursor-coated silicon material. Put the precursor-coated silicon material into the constant temperature zone of the tube furnace, heat it in the air atmosphere at 30 °C / min to 230 °C, keep it warm for 2 hours, let it cool naturally, and pass nitrogen gas for 20 min, close the tube furnace, and then 10°C / min to raise the temperature to 600°C, keep it warm for 2 hours, s...

Embodiment 2

[0047] Weigh 14g PEG (M W :1000) and 50g CA (C 6 h 8 o 7 ·H 2 (0), add 150ml dehydrated alcohol (95%), after magnetic stirring is to dissolving, then add 25g cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O), magnetically stirred for 50min to obtain a precursor solution. Add 45g of graphite (with a particle size of 16 μm) to the precursor solution, stir magnetically for 1 hour, slowly add 5g of nano-silicon (with a particle size of 200nm) under stirring, continue magnetic stirring for 2.5 hours, and suction filter the resulting slurry 1. After washing several times, put it in a vacuum drying oven, and dry at 80° C. for 5 hours to obtain a silicon material coated with a precursor. Put the precursor-coated silicon material into the constant temperature zone of the tube furnace, heat it in the air atmosphere at 30°C / min to 230°C, keep the temperature constant for 2 hours, let it cool naturally, and then pass nitrogen gas for 20min, close the tube furnace, and then The temp...

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Abstract

The invention relates to the field of lithium ion batteries, and discloses a silicon negative electrode material and a negative electrode sheet coated with carbon nanotubes, a preparation method thereof and a lithium ion battery. The preparation method of the silicon negative electrode material comprises the following steps: (1) dissolving polyethylene glycol, citric acid and / or citric acid monohydrate and transition metal salt in a solvent to obtain a precursor solution; (2) mixing the precursor solution with the silicon material, filtering, washing, and then drying under the condition of isolating air to obtain the precursor-coated silicon material; (3) heating the precursor-coated silicon material in an air atmosphere to 200-280 DEG C for sintering for 1.5-3.5 hour, naturally cooling toobtain MOx / Si composite pow; (4) heating the MOx / Si composite powder under the protection of inert gas and / or weak reducing gas to 400-800 DEG C for sintering for 1-5h. The silicon negative electrodematerial obtained by the method has stable electrochemical performance, can avoid damage to the structure of carbon nanotubes, has simple process, does not use flammable and explosive alkane as carbon source, and has high safety.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a carbon nanotube-coated silicon negative electrode material, a negative electrode sheet, a preparation method thereof, and a lithium-ion battery. Background technique [0002] With the development of the new energy industry, people have put forward higher and higher requirements for lithium-ion batteries. Improving energy density and extending cycle life have become urgent problems for lithium-ion batteries. Traditional graphite anode materials have been difficult to meet the needs of the development of the new situation. Due to its high theoretical specific capacity (4200mAh / g), low potential for lithium intercalation and extraction, and abundant silicon reserves, silicon anode materials have become the most promising anode materials for next-generation lithium-ion batteries. However, silicon anode materials also have the following problems: 1. The huge volume ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 陈梅蓉蒋玉雄翁松清
Owner 厦门高容新能源科技有限公司
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