A high-capacity silicon-carbon negative electrode active material and its preparation method and application

A technology of negative electrode active materials and silicon carbon materials, which is applied in the direction of battery electrodes, structural parts, electrical components, etc., can solve the problems of poor cycle performance, complex preparation process and high cost of high capacity silicon carbon negative electrode active materials, and achieve the promotion of industrialization The process and process are simple and the effect of not easy to separate

Active Publication Date: 2021-04-13
SHAANXI COAL & CHEM TECH INST
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In order to solve the problems of poor cycle performance, complex preparation process, low output and high cost of high-capacity silicon-carbon negative electrode active materials, the present invention provides nano-silicon, micron flake graphite, carbon nanotubes and pyrolytic carbon as raw materials, and utilizes ball milling Simple and easy-to-scale technologies such as spray drying and spray drying are used to construct silicon-carbon materials with good pore structure and conductive network; and a process method for preparing high-capacity, long-cycle silicon-carbon negative electrode active materials (800-1800mAh / g) with graphite materials

Method used

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  • A high-capacity silicon-carbon negative electrode active material and its preparation method and application
  • A high-capacity silicon-carbon negative electrode active material and its preparation method and application
  • A high-capacity silicon-carbon negative electrode active material and its preparation method and application

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Experimental program
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Effect test

Embodiment 1

[0036] Material Synthesis:

[0037] (1) Ball mill silicon with a particle size of 80nm, flake graphite with a length of 10um and a thickness of 10nm, carbon nanotubes with a diameter of 5nm and a diameter of 60-100um, pitch and polyvinylpyrrolidone in ethylene glycol for 5 hours , with a rotational speed of 300rpm; wherein, the mass ratio of silicon, graphite, carbon nanotubes, and pitch pyrolytic carbon is 70:10:5:15; the mass ratio of silicon to polyvinylpyrrolidone is 100:3;

[0038] (2) Dilute the ball-milled slurry to a solid content of 25%, ultrasonicate at 5°C for 30min, with an ultrasonic power of 1300W, and then stir for 5h at a speed of 500rpm;

[0039] (3) Use two-fluid spray equipment for granulation, and the inlet and outlet temperatures are set to 250 and 120°C respectively;

[0040] (4) the product obtained by spraying in N 2 Heat treatment in the atmosphere, 480°C for 2h + 850°C for 3h, to prepare silicon carbon material A.

[0041] (5) Mix the prepared silico...

Embodiment 2

[0047] Material Synthesis:

[0048] (1) Silicon with a particle size of 50nm, flake graphite with a length of 10-20um and a thickness of 60nm, carbon nanotubes with a width and diameter of 50nm and 20um, carbon source and sodium dodecylsulfonate Ball milling was carried out in ethanol at a speed of 2000rpm, and the ball milling time was 0.2h; wherein, the mass ratio of silicon, graphite, carbon nanotubes, and carbon source pyrolytic carbon was 55:5:8:32; the ratio of silicon to sodium dodecylsulfonate The mass ratio is 100:15; the carbon source in the carbon source pyrolytic carbon is a mixture of polyimide and polyvinyl butyral in any proportion;

[0049] (2) Adjust the solid content of the slurry after ball milling to 40%, and after ultrasonication for 30 minutes, stir for 0.5 hour at a speed of 2000 rpm;

[0050] (3) Use spray equipment to granulate, and the inlet and outlet temperatures are set to 150 and 90°C respectively;

[0051] (4) the product obtained by spraying i...

Embodiment 3

[0057] Material Synthesis:

[0058] (1) Silicon with a particle size of 150nm, flake graphite with a length of 8-10um and a thickness of 40nm, carbon nanotubes with a diameter width and diameter of 8-15nm and 30um, sucrose pyrolytic carbon and triton Carry out ball milling in acetone, rotating speed 1000rpm, ball milling time 2h; Wherein, the mass ratio of silicon, graphite, carbon nanotube, sucrose pyrolytic carbon is 40:10:10:40; The mass ratio of silicon and triton is 100: 5;

[0059] (2) adjust the solid content of the slurry after ball milling to 30%, after ultrasonication for 30min, stir for 3h, and the stirring speed is 1000rpm;

[0060] (3) Use spray equipment to granulate, and the inlet and outlet temperatures are 160 and 70°C respectively;

[0061] (4) the product obtained by spraying in N 2 Heat treatment is carried out in the atmosphere, the temperature is 600° C., and the treatment time is 6 hours, and the silicon carbon material A is obtained.

[0062] (5) Th...

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Abstract

The invention discloses a high-capacity silicon-carbon negative electrode active material and its preparation method and application. The high-capacity silicon-carbon negative electrode active material has a specific capacity of 800-1500mAh / g, and is formed by mixing silicon-carbon materials and graphite materials. Silicon carbon material is prepared from nano-silicon, flake graphite, carbon nanotubes and carbon source through ball milling, spray drying and heat treatment to obtain microspherical particles, in which nano-silicon is dispersed on the surface of flake graphite, and carbon nanotubes are interspersed between carbon nanotubes and flake graphite In the formed pores, pyrolytic carbon from carbon sources is coated on the surface of nano-silicon, and the surface and pores of spherical particles formed by nano-silicon, flake graphite and carbon nanotubes; silicon-carbon materials account for the total of high-capacity silicon-carbon negative electrode active materials. 25% to 80% of the mass. The active material is uniformly mixed with a conductive agent and a binder, and coated or deposited on copper foil, nickel foam, copper foam or carbon fiber paper to be used as a negative electrode of a lithium ion battery. The preparation method of the invention has simple process, low cost and is suitable for large-scale preparation of long-cycle and silicon-carbon materials.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-capacity silicon-carbon negative electrode active material (800-1800mAh / g) and a preparation method and application thereof. Background technique [0002] In recent years, with the aggravation of environmental pollution and energy shortages, emerging industries represented by new energy vehicles have developed rapidly. As a power battery with long cycle life, high power density, low self-discharge rate and green environmental protection, lithium-ion battery has ushered in new opportunities, but also faces great challenges. At present, the energy density and cruising range of power lithium-ion batteries are difficult to meet the needs of electric vehicles. [0003] Graphitized carbon material is the most commonly used negative electrode material for commercial lithium-ion batteries. It has good conductivity and stable cycle, but its theoretical sp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/362H01M4/386H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 杨时峰张大鹏曹国林刘万田占元邓增社
Owner SHAANXI COAL & CHEM TECH INST
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