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Composite silicon negative electrode material, and preparation method and application thereof

A silicon negative electrode and nano-composite technology, applied in negative electrodes, electrode manufacturing, chemical instruments and methods, etc., can solve problems such as difficult volume expansion, degradation of negative electrode material cycle performance, difficult preparation of active silicon layers, etc., to achieve a simple and easy preparation process control, improve cycle performance, and avoid direct contact

Active Publication Date: 2016-03-16
DINGYUAN NEW ENERGY TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] CN101777651A discloses a lithium-ion battery negative electrode material, including active material silicon powder and volume buffer silica, wherein silicon is coated or partially coated on the surface of silicon dioxide particles. It is prepared by mixing silicon oxide with carbon reducing agent, and then sintering at high temperature in vacuum. However, it is difficult to prepare a dense active silicon layer through the reduction reaction of carbon and silicon dioxide in this method, and the thickness of the silicon layer is also difficult to control, resulting in the cycle of negative electrode materials. The performance will be significantly deteriorated and the capacity of the negative electrode material is also difficult to control
[0007] CN102709563A discloses a silicon negative electrode material for lithium-ion batteries. The negative electrode material includes nano-silicon powder and a silicon dioxide coating layer coated on the surface of nano-silicon. The patented silicon negative electrode disperses nano-silicon in sodium silicate solution, Then add graphite and inorganic acid to precipitate and coat copper foil, and dry it at 150°C. This method is difficult to ensure that the silicon dioxide is completely covered on the silicon surface, and the graphite conductive network is only mechanically mixed in the silicon negative electrode material. , so it is also difficult to suppress volume expansion during silicon cycling
[0008] The technical solutions disclosed in CN101777651A and CN102709563A are to coat silicon on the buffer surface or coat the buffer layer on the silicon surface. Although the volume expansion of part of the silicon can be suppressed, the electrical conductivity of the silicon itself has not been significantly improved, resulting in a long cycle life that cannot be guaranteed.

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  • Composite silicon negative electrode material, and preparation method and application thereof
  • Composite silicon negative electrode material, and preparation method and application thereof
  • Composite silicon negative electrode material, and preparation method and application thereof

Examples

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Embodiment 1

[0060] A composite silicon negative electrode material prepared by the following method:

[0061] (1) Select silicon powder with a median particle size of 50-80nm as nano-silicon, place it in a rotary furnace with a rotating speed of 20r / min, and feed argon gas with a volume ratio of 1:0.5 at a gas flow rate of 0.5L / min. Oxygen mixed gas, heat treatment at 500°C for 1 hour, to obtain primary heat treatment silicon powder;

[0062] Mix primary heat-treated silicon powder, bismuth powder and tin powder at a mass ratio of 100:5:5 and put them into a high-energy ball mill, and put 0.5mm zirconium balls into them, and then pass in argon protective gas for high-energy ball milling, in which the ball mill The rotating speed is 3000r / min, the mass ratio of balls and powder is 10:1, after ball milling for 20h, the ball milling mixed powder is obtained; Heat treatment at ℃ for 2 hours to obtain the first precursor;

[0063] (2) Proportioning the first precursor and the asphalt powder ...

Embodiment 2

[0071] A composite silicon negative electrode material prepared by the following method:

[0072] (1) Select silicon powder with a median particle size of 150-200nm as nano-silicon, place it in a rotary furnace with a rotating speed of 20r / min, and then feed a mixed gas of oxygen and argon with a volume ratio of 1:1, and the gas flow rate is 2L / min, heat treatment at 600°C for 1h, to obtain a heat-treated silicon powder;

[0073] Mix primary heat-treated silicon powder and titanium dioxide powder with a median particle size of 50nm at a mass ratio of 100:10 and put them into a rotary furnace, then feed ammonia and argon at a volume ratio of 1:1 at a gas flow rate of 1L / min. gas mixture, heat treatment at 900°C for 1 hour to obtain the first precursor;

[0074] (2) The first precursor is placed in a rotary furnace with a rotating speed of 10rpm / min, methane gas is introduced at a gas flow rate of 0.5L / min, and gas phase coating treatment is performed at 900°C to obtain the sec...

Embodiment 3

[0080] A composite silicon negative electrode material prepared by the following method:

[0081] (1) Put silicon powder with a median particle size of 1 to 30nm in a rotary furnace with a rotating speed of 30r / min, and then feed a mixed gas of neon gas and oxygen with a volume ratio of 1:0.1 at a gas flow rate of 0.8L / min , thermal oxidation treatment was carried out at 1200°C for 1 hour to obtain a heat-treated silicon powder;

[0082] Mix primary heat-treated silicon powder, aluminum powder and tin powder in a mass ratio of 100:5:5 and put them into a high-energy ball mill, and put 1mm zirconium balls into it, and then pass in argon protective gas for high-energy ball milling, wherein the ball mill speed 2000r / min, the mass ratio of balls and powder is 50:1, after ball milling for 30h, the ball milled mixed powder is obtained; then the ball milled mixed powder is placed in a rotary furnace with a rotating speed of 20r / min, and argon gas is introduced, and the temperature is...

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Abstract

The invention relates to a composite silicon negative electrode material. The composite silicon negative electrode material comprises nanometer silicon, a nanometer composite layer coating the surface of nanometer silicon and a conductive carbon layer uniformly coating the nanometer composite layer, wherein the nanometer composite layer is silicon oxide and metal alloy. According to the composite silicon negative electrode material with a three-layer structure, the nanometer composite layer composed of the silicon oxide and the metal alloy coating the surface of the silicon oxide effectively reduces volume expansion of the nanometer silicon, maintains the characteristic of high conductivity of the silicon material, improves mobility of lithium ions, prevents direct contact between a silicon negative electrode and an electrolyte, and can form a hard SEI film on the surface of the composite silicon negative electrode material, thereby allowing the cycle performance of the material to be substantially enhanced. The composite silicon negative electrode material has the characteristics of high capacity (greater than 1500 mAh / g), long cycle life (with a capacity retention ratio of more than 90% after 300 cycles) and high conductivity. The preparation method for the composite silicon negative electrode material is simple, easily controllable, and applicable to industrial production.

Description

technical field [0001] The present invention relates to a composite silicon negative electrode material, a preparation method thereof, and a lithium ion battery prepared using the negative electrode material, which belong to the field of lithium ion battery negative electrode materials and electrochemistry. Background technique [0002] As an energy storage device, lithium-ion batteries have the advantages of high energy density, small self-discharge, wide operating voltage range, no memory effect, long service life, and no environmental pollution. They have been widely used in 3C consumer electronics, energy storage, and new energy vehicles. and other fields. The key electrode material of lithium-ion battery is the final decisive factor of battery performance, and the negative electrode material plays a vital role in improving the performance of lithium-ion battery. At present, the application of negative electrode materials is mainly based on traditional graphite material...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62H01M4/36H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M10/0525H01M4/38H01M4/0471H01M4/1395H01M4/483H01M2004/027C01B33/021Y02E60/10C01B32/05B22F9/04C01B33/02C01B33/113H01M4/485H01M4/626B22F1/142
Inventor 何鹏李胜岳敏郭锷明
Owner DINGYUAN NEW ENERGY TECH CO LTD
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