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Composite material, preparation method and electrochemical device

A composite material, silicon carbide layer technology, applied in circuits, electrical components, battery electrodes, etc., can solve the problems of high proportion of filling materials and coating materials, reduced capacity of modified natural graphite, and high cost of graphitization process. The effect of saving soft carbon filling and graphitization processes, improving kinetic properties, and shortening the preparation cycle

Pending Publication Date: 2022-08-02
CALB CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Filling with fillers, soft carbon coating and graphitization are usually used to improve the cycle performance of natural graphite particles. However, due to the large proportion of fillers and coating materials added to the formed natural graphite, on the one hand, the capacity of modified natural graphite is reduced.
On the other hand, the cost of the graphitization process is high and the cycle is long, which puts forward higher requirements for the large-scale application of natural graphite

Method used

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  • Composite material, preparation method and electrochemical device
  • Composite material, preparation method and electrochemical device

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preparation example Construction

[0013] The preparation method of the composite material of the present invention includes: S1, coating the surface of the natural graphite core with a silicon carbide layer. The preparation method of the composite material of the present invention directly protects the silicon carbide layer on the surface of the natural graphite core, which can save the process of soft carbon filling and graphitization of the natural graphite, thereby greatly reducing the material use cost and shortening the material preparation period.

[0014] In an optional embodiment, the preparation method may further include: S2, coating the surface of the silicon carbide with a carbon layer.

[0015] In alternative embodiments, the coating is a chemical vapor deposition coating, a spray drying coating, or a dipping coating.

[0016] The electrochemical device of the present invention includes the above-mentioned composite material.

[0017] The present invention is further described below through speci...

Embodiment 1

[0020] Spherical natural graphite with a mass of 500 g and a particle size of D50 of 5 μm was weighed and placed in a CVD rotary furnace. Connect the gas circuit, pass trichloromethylsilane (CH 3 SiCl 3 ) and hydrogen (H 2 ), the gas flow ratio is 3:2, and the air is ventilated for half an hour to replace the air in the rotary furnace; after replacing the gas, the temperature is raised from room temperature to 1500 degrees Celsius at a heating rate of 10 °C / min, and kept for 2 hours to complete the silicon carbide coating.

[0021] After the silicon carbide coating is completed, the temperature is lowered to 400 ° C, and the trichloromethylsilane (CH 3 SiCl 3 ) and hydrogen (H 2 ) gas flow valve, connected to argon, hydrogen, propylene gas flow valve, the flow rate, gas flow ratio is 7:1:2, the rotary furnace is heated to 750 °C at 5 °C / min, and the temperature is kept at 750 °C for 1h. Coated with conductive carbon, after the temperature dropped to room temperature, the ...

Embodiment 2

[0032] Spherical natural graphite with a mass of 500 g and a particle size of D50 of 10 μm was weighed and placed in a CVD rotary furnace. Connect the gas circuit, pass trichloromethylsilane (CH 3 SiCl 3 ) and hydrogen (H 2 ), the gas flow ratio is 3:2, and the air is ventilated for half an hour to replace the air in the rotary furnace; after replacing the gas, the temperature is raised from room temperature to 1500 degrees Celsius at a heating rate of 10 °C / min, and the temperature is maintained for 4 hours to complete the silicon carbide coating.

[0033] After the silicon carbide coating is completed, the temperature is lowered to 400 ° C, and the trichloromethylsilane (CH 3 SiCl 3 ) and hydrogen (H 2 ) gas flow valve, connected to the argon, hydrogen and propylene gas flow valves, the flow rate and gas flow ratio are 7:1:2, the rotary furnace is heated to 850 °C at 5 °C / min, and kept at 850 °C for 3 hours. Coated with conductive carbon, after the temperature dropped t...

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Abstract

The invention provides a composite material and a preparation method thereof, the composite material comprises an inner core and a shell layer, and the shell layer is arranged on the outer surface of the inner core; the inner core comprises natural graphite, and the shell layer comprises a silicon carbide layer; the ratio of the particle size D50 of the inner core to the thickness d of the shell layer is 5-150, the particle size D50 of the inner core is 5 [mu] m-20 [mu] m, and the thickness d of the shell layer is 0.012 [mu] m-0. 2 [mu] m. The SiC layer with high gram volume and high mechanical strength is coated on the outer layer of the natural graphite, so that the surface layer strength of the material can be improved. Therefore, the consumption of active lithium due to surface damage caused by non-uniform stress distribution caused by lithium deintercalation and intercalation of natural graphite is relieved. The gram volume of the natural graphite is improved, and the cycle life of the natural graphite is prolonged. Meanwhile, according to the preparation method of the composite material, soft carbon filling and graphitization procedures for natural graphite can be omitted, the use cost of the material can be greatly reduced, and the preparation period of the material can be shortened.

Description

technical field [0001] The invention belongs to the field of chemical power sources, and in particular relates to a composite material, a preparation method thereof, and an electrochemical device comprising the same. Background technique [0002] During the battery cycle process of natural graphite anode material, the abundant active surface brought by the large number of pores inside the natural graphite and the side reaction with the electrolyte are the main reasons for the battery cycle failure. Therefore, in the modification strategy of natural graphite, the pores of natural graphite are filled to prevent the consumption of active lithium at the pores during the cycle. Usually, filler filling, soft carbon coating and graphitization are used to improve the cycle performance of natural graphite particles. However, due to the large proportion of added filler and coating substances, the capacity of modified natural graphite is reduced on the one hand. On the other hand, the...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/583H01M4/587
CPCH01M4/366H01M4/587H01M4/583Y02E60/10
Inventor 周向龙王志敏李彦龙李奎
Owner CALB CO LTD