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Preparation method of silicon-carbon anode material and lithium ion battery

A negative electrode material, silicon carbon technology, applied in the direction of battery electrodes, secondary batteries, circuits, etc., can solve the problems of unfavorable industrial development and application, complicated steps, poor cycle performance, etc., achieve excellent electrochemical cycle stability and easy industrialization The effect of simple production and process

Active Publication Date: 2018-12-07
湖北融通高科先进材料集团股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Chinese patent CN102651476B discloses a silicon-carbon composite negative electrode material and its preparation method. The silicon-carbon composite negative electrode material uses graphite as the core and nano-silicon as the shell, and is prepared by the charge adsorption method of positive and negative ion surfactants in the solution. , although this method can achieve uniform dispersion of nano-silicon on the graphite surface, but there is no amorphous carbon layer to cover nano-silicon, which will lead to huge volume expansion and structural collapse of nano-silicon during the process of delithiation and intercalation, resulting in poor cycle performance. poor
[0004] For example, Hou X et al. (Journal of Power Sources, 2014, 248(2): 721-728) disclose a graphite-based nano-Si uniformly dispersed on the graphite surface, and amorphous carbon as a shell coated nano-Si The silicon-carbon composite material on the surface, although the obtained silicon-carbon material has excellent cycle performance, but this method uses multiple spray drying processes, the steps are complicated, the reaction process is difficult to control, and the stability is poor, which is not conducive to industrial development and application

Method used

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  • Preparation method of silicon-carbon anode material and lithium ion battery
  • Preparation method of silicon-carbon anode material and lithium ion battery
  • Preparation method of silicon-carbon anode material and lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0045] Will D 50 100nm of 2g nano-silicon and D 50 6g flake natural graphite of 8μm is mixed evenly in solid phase, vibrating and sieving, the sieve is 600 mesh, the power of vibrating sieving is 300KW, and then mixed with 2g of high-temperature asphalt in solid phase, vibrating and sieving, the sieve is 250 Mesh sieve, the power of vibrating sieving is 300KW to obtain nano-silicon / graphite / high-temperature asphalt composite material, the above-mentioned composite material is formed by vibration, the frequency of vibration forming is 500 times / min, and the time of vibration forming is 20min to obtain dense powder In an inert gas environment, raise the temperature of the obtained compact powder to 500°C at the first heating rate of 2°C / min, keep it for 4h, then raise the temperature to 950°C at the second heating rate of 3°C / min, and keep it for 4h , natural cooling, crushing and crushing to obtain the silicon carbon negative electrode material.

Embodiment 2

[0047] Will D 50 100nm of 2g nano-silicon and D 50 6g flake natural graphite of 20μm is mixed evenly in solid phase, vibrating and sieving, the sieve is 450 mesh, the power of vibrating sieving is 300KW, then mixed with 1g glucose in solid phase, vibrating and sieving, the sieve is 250 mesh Sieve, the power of vibrating sieving is 300KW to obtain nano-silicon / graphite / glucose composite material, the above-mentioned composite material is vibrated, the frequency of vibration forming is 600 times / min, the time of vibration forming is 20min, and dense powder is obtained. The obtained dense powder was heated up to 500°C at the first heating rate of 8°C / min in an inert gas environment, and kept for 5 hours, and then raised to 800°C at the second heating rate of 0.5°C / min, kept for 4 hours, and naturally Cool down, crush and pulverize to obtain silicon carbon negative electrode material.

Embodiment 3

[0049] Will D 50 100nm of 3g nano-silicon and D 50 8g flake natural graphite of 10μm is mixed evenly in solid phase, vibrating and sieving, the sieve is 350 mesh, the power of vibrating sieving is 500KW, and then mixed with 4g high-temperature asphalt in solid phase, vibrating sieving, sieving It is a 250-mesh sieve, and the power of vibrating sieving is 500KW to obtain a nano-silicon / graphite / high-temperature asphalt composite material. The composite material is vibrated and formed. The frequency of vibration forming is 20 times / min, and the time of vibration forming is 600min. For dense powder, heat the obtained dense powder to 400°C at the first heating rate of 0.5°C / min in an inert gas environment, keep it warm for 5 hours, and then raise the temperature to 1100°C at the second heating rate of 1°C / min, Keeping it warm for 5 hours, cooling down naturally, crushing and pulverizing to obtain the silicon carbon negative electrode material.

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Abstract

The invention discloses a preparation method of a silicon-carbon anode material and a lithium ion battery. The preparation method includes: mixing nano-silicon with graphite solid phase, sieving the mixture, mixing the mixture with an amorphous carbon precursor solid phase, sieving the mixture, performing vibrating shaping, and sintering the product to obtain the silicon-carbon anode material. Bymeans of sieving, the graphite, nano-silicon and amorphous carbon precursor are dispersed, so that the surface of graphite can be uniformly coated with the nano-silicon and the surface of nano-siliconcan be uniformly coated with the amorphous carbon precursor; through the vibrating shaping, surface-to-surface contact between the amorphous carbon precursor and the nano-silicon and between the nano-silicon and the graphite is achieved without existence of a gap; through the sintering step, a volatile substance can be slowly volatilized from interior to exterior, so that a problem of forming pores since a huge gas pressure is generated from the volatile substance can be avoided. The silicon-carbon anode material, when being used for producing the lithium ion battery, shows excellent electrochemical cyclic stability.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for preparing a silicon-carbon negative electrode material and a lithium-ion battery. Background technique [0002] In recent years, with the increase in the demand for new energy electric vehicle cruising range, the current commercial graphite anode material (theoretical specific capacity is 372mAh / g) has been difficult to meet the current demand, and it is urgent to develop a high specific capacity anode material. Elemental silicon is most likely to replace commercial graphite anode materials due to its high theoretical specific capacity (4200mAh / g) and low lithium intercalation potential, but elemental silicon will produce a huge volume effect ( up to 300%), leading to the collapse of the electrode structure and the peeling off of the electrode material, resulting in the separation between the electrode materials, the electrode material and the conductiv...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/364H01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 康飞宇李成飞贺艳兵何中林蒋克林武洪彬李宝华程光春林平
Owner 湖北融通高科先进材料集团股份有限公司
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