A kind of carbon/silicon/carbon composite material and its preparation method and application

A carbon composite material and carbon material technology, applied in structural parts, electrical components, battery electrodes, etc., can solve the problems of difficulty in meeting the high requirements of lithium-ion batteries, low cycle capacity retention rate, equipment requirements and high energy consumption, and achieve The effect of shortening the preparation cycle, improving the interface compatibility, and improving the production efficiency

Active Publication Date: 2020-11-24
DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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  • Application Information

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Problems solved by technology

[0002] With the rise of the new energy field, graphite, a commercial lithium-ion anode material, is approaching its theoretical capacity, which is difficult to meet the current high requirements for lithium-ion batteries
The technical problem to be solved by the present invention is to overcome the shortcomings of the existing silicon-carbon composite materials such as small charge-discharge capacity, low first-time efficiency or low retention rate of long-term use cycle capacity, which cannot be applied.
[0003] Silicon-based materials have a high theoretical specific capacity, but the rapid failure of the battery due to the huge volume expansion during the charging and discharging process limits its application and promotion.
At present, the main methods to solve the volume expansion of silicon-based materials during charging and discharging are: (1) Chinese patents CN106025218A, CN106328909A and CN106067547A nanometerize silicon-based materials and then compound them with carbon materials to prepare silicon-carbon composite materials, but due to silicon-based materials The strength of its own is high, and the energy consumption and time-consuming of nanometerization are high, and the nanometerized silicon is easy to agglomerate; (2) Chinese patents CN106328909A and CN106356508A first prepare a silicon-oxygen precursor with a specific structure, and then combine the silicon-oxygen precursor with Magnesium powder is roasted and reduced at high temperature under protective gas to obtain silicon. The traditional sol-gel method for preparing silicon oxide has a long preparation cycle, and the equipment required for the reduction process and energy consumption are relatively high.

Method used

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  • A kind of carbon/silicon/carbon composite material and its preparation method and application
  • A kind of carbon/silicon/carbon composite material and its preparation method and application
  • A kind of carbon/silicon/carbon composite material and its preparation method and application

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Effect test

Embodiment 1

[0050] Step 1: Add 15g of artificial graphite to 450mL of 30% hydrogen peroxide, react at 50°C for 3h under stirring conditions of 800r / min to oxidize the artificial graphite, filter the reacted mixture and wash the filter cake with deionized water, when washing After the liquid pH=7, the filter cake was dried to a constant weight to obtain 14.52 g of oxidized artificial graphite.

[0051] Step 2: Add 10g of oxidized artificial graphite to the flat bottom flask, then add 10mL of deionized water and 30mL of absolute ethanol, adjust the resulting mixture to pH = 2 with 0.1mol / L hydrochloric acid, then add 2g of vinyl triethoxy Silane and 7.5g tetraethyl orthosilicate, the mixture was ultrasonically treated for 20min, then transferred to a microwave reactor with a power of 300W, microwaved at 50°C for 2min, filtered, the filter cake was washed with absolute ethanol, and vacuum-dried at 150°C After 2h, 11.12g of precursor 1 was obtained.

[0052] Step 3: Mix 5g of precursor 1 and...

Embodiment 2

[0056] Step 1: Add 15g of natural graphite to 400mL of 65% nitric acid, react at 25°C and 800r / min for 4h to oxidize the natural graphite, filter the reacted mixture and wash the filter cake with deionized water, when the pH of the washing solution After =7, the filter cake was dried to constant weight to obtain 14.34g of oxidized natural graphite.

[0057] Step 2: Add 10g of oxidized natural graphite to a flat-bottomed flask, then add 10mL of deionized water and 40mL of isopropanol, adjust the resulting mixture to pH = 2 with 0.1mol / L nitric acid, then add 2.5g of aminopropyl triethoxy Silane and 6.8g tetraethyl orthosilicate, the mixture was ultrasonically treated for 15min, then transferred to a microwave reactor with a power of 200W, microwaved at 30°C for 1min, filtered, the filter cake was washed with absolute ethanol, and vacuum-dried at 150°C After 2h, 10.62g of precursor 1 was obtained.

[0058] Step 3: Mix 5g of precursor 1 and 2g of nano-magnesium powder and place ...

Embodiment 3

[0062] Step 1: Add 17g of mesocarbon microspheres to 400mL of 98% concentrated sulfuric acid, react at 40°C for 3h under 600r / min stirring conditions to oxidize the mesocarbon microspheres, filter the reacted mixture and use deionized The filter cake was washed with water, and when the pH of the washing solution was 7, the filter cake was dried to a constant weight to obtain 15.89 g of oxidized mesocarbon microspheres.

[0063] Step 2: Add 10 g of oxidized mesophase carbon microspheres to a flat-bottomed flask, then add 10 mL of deionized water and 25 mL of ethyl acetate, adjust the resulting mixture to pH = 2 with 1 mol / L sulfuric acid, and then add 8 g of ethyl orthosilicate , after the mixture was sonicated for 20 min, it was transferred to a microwave reactor with a power of 400 W, microwaved at 35 °C for 5 min, filtered, the filter cake was washed with absolute ethanol, and 10.82 g of precursor 1 was obtained after vacuum drying at 150 °C for 2 h.

[0064] Step 3: Mix 5g ...

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Abstract

The invention relates to a carbon / silicon / carbon composite material and preparation method and application thereof. The composite material takes a carbon material as a core, and a nanometer silicon layer and a nanometer carbon layer wrap a surface of the carbon material. According to the preparation method of the carbon / silicon / carbon composite material, a silicon oxide layer is coated on the surface of the carbon material by a mode of absorbing organosilane with microwave, the preparation period is greatly shortened, and the production efficiency is improved; a silicon oxide is reduced to silicon by mechanical ball-grinding of nanometer metal particles with high reduction performance under a room temperature, and the energy consumption is reduced; and a carbon layer is coated on a siliconlayer by high-temperature roasting to obtain the carbon / silicon / carbon composite material. During the charge-discharge process of the carbon / silicon / carbon composite material, the volume change of asilicon electrode material can be effectively controlled, the electrode structure is maintained complete, and the carbon / silicon / carbon composite material is large in cycle capacity and long in service lifetime and has wide application market.

Description

technical field [0001] The invention relates to the field of lithium-ion battery negative electrode materials, in particular to a silicon-carbon composite material used for lithium-ion battery negative electrodes, a preparation method and application thereof. Background technique [0002] With the rise of the new energy field, graphite, a commercial lithium-ion anode material, is approaching its theoretical capacity, which is difficult to meet the current high requirements for lithium-ion batteries. The technical problem to be solved by the present invention is to overcome the disadvantages of the existing silicon-carbon composite materials such as small charge and discharge capacity, low first-time efficiency or low capacity retention rate of long-term use cycle, which cannot be applied. [0003] Silicon-based materials have a high theoretical specific capacity, but the rapid failure of the battery due to the huge volume expansion during the charge and discharge process lim...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36
CPCH01M4/362H01M4/366Y02E60/10
Inventor 成小康朱金保彭果戈
Owner DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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