Preparation method of micron silicon-carbon composite negative electrode material with long cycle life

A silicon-carbon composite and negative electrode material technology, applied in the direction of negative electrodes, battery electrodes, active material electrodes, etc., can solve the problems of increasing the specific surface area of ​​materials, restricting cycle stability, and integrity of difficult electrodes

Active Publication Date: 2020-06-05
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the ability of active particles to effectively buffer internal stress decreases rapidly as the size increases
Studies have shown that when the size of silicon active particles exceeds 150 nm, they will inevitably break into smaller nanoparticles during the charging and discharging process, which not only causes some active materials to lose electrical contact, but also increases the specific surface area of ​​the material. Exposing the fresh silicon surface makes the SEI film continue to grow repeatedly on the surface of the particle, seriously restricting its cycle stability
[00...

Method used

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  • Preparation method of micron silicon-carbon composite negative electrode material with long cycle life
  • Preparation method of micron silicon-carbon composite negative electrode material with long cycle life
  • Preparation method of micron silicon-carbon composite negative electrode material with long cycle life

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Embodiment 1

[0029] This embodiment provides a method for preparing a micro-silicon-carbon composite negative electrode material with a long cycle life, comprising the following steps:

[0030] 1) Place 1.0 g of silicon powder with a particle size distribution range of 3 μm to 5 μm in the crucible, transfer it to a tube furnace, and heat up at a rate of 10 ºC / min under an argon flow rate of 50 mL / min Heating to 1000 ºC, and then feeding methane gas at this temperature with a flow rate of 50 mL / min and a reaction time of 60 min. After the reaction, the methane gas was turned off, the argon flow was kept constant, the temperature was lowered to 400 ºC at a rate of 10 ºC / min, and then naturally cooled to room temperature to obtain carbon-coated micron silicon particles.

[0031] 2) Ultrasonic dispersion of 500 mg of micron silicon carbon particles obtained in step 1) in a mixed solvent of 100 mL of water and 100 mL of ethanol to obtain a uniform dispersion;

[0032] 3) Add 6 g of sod...

Embodiment 2

[0038] Embodiment 2: Different from Embodiment 1, the flow rate of feeding methane gas in step 1) is adjusted to 30 mL / min, and the rest are the same as Embodiment 1, and will not be repeated here.

Embodiment 3

[0039] Example 3: The difference from Example 1 is that step 1) put 1.0 g of silicon powder with a particle size distribution range of 3 μm to 5 μm in the crucible, transfer it to a tube furnace, and heat it under 40 mL / min of argon Under the air flow, the heating rate was 7 ºC / min to 950 ºC, and then methane gas was introduced at this temperature, the flow rate was 50 mL / min, and the reaction time was 40 min. After the reaction, the methane gas was turned off, the argon flow was kept constant, the temperature was lowered to 400 ºC at a rate of 7 ºC / min, and then naturally cooled to room temperature to obtain carbon-coated micron silicon particles.

[0040] The rest are the same as in Embodiment 1, and will not be repeated here.

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Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a preparation method of a micron silicon-carbon composite negative electrode material with long cycle life, the composite negative electrode material prepared by the method has a tough multistage buffer structure, micron silicon particles crushed in a cycle process can be stabilized internally, and a fresh surface exposed by cracking is protected; and the graphene compact network with high strength and high modulus on the outer layer can maintain the structural integrity of the internal silicon-carbon active particles in the compaction process to the greatest extent. Meanwhile, internal silicon-carbon active particles (SiMP(at)C) are tightly connected into a mechanical and electrical whole through a graphene network with a compactly contracted outer layer, so that the electrode structure is reinforced and toughened, and effective mechanical buffering and continuous and rapid electron transferare realized in the lithium de-intercalation and intercalation process.

Description

technical field [0001] The invention belongs to the technical field of battery materials, and in particular relates to a preparation method of a micron silicon-carbon composite negative electrode material with long cycle life. Background technique [0002] As a new generation of lithium-ion battery anode material, silicon has abundant reserves, and its theoretical lithium storage specific capacity is the highest among all alloyed lithium storage elements, so it has great potential to replace graphite as the anode material of commercial lithium-ion batteries. At this stage, relevant research on silicon anodes has achieved remarkable results. However, a large number of applications of nanotechnology, including the use of nano-silicon as the active material to construct electrode materials and nano-design of carbon structures, etc., reduce the tap density and electrode density of materials, thus restricting the improvement of the volume performance of silicon anodes. Micro-sil...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/587H01M10/0525
CPCH01M4/362H01M4/386H01M4/587H01M10/0525H01M2004/027Y02E60/10H01M4/366H01M4/625H01M4/0428H01M4/0471C01P2006/10C01B33/02C01B32/198H01M4/583H01M2004/021
Inventor 杨全红陈凡奇韩俊伟肖菁孔德斌陶莹
Owner TIANJIN UNIV
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