High-performance silicon-carbon composite with core-shell structure, and preparation method and application of silicon-carbon composite in lithium ion battery

A technology of silicon-carbon composite materials and core-shell structure, applied in battery electrodes, secondary batteries, structural parts, etc., can solve the problems of inability to form a stable SEI film, capacity fading, and Coulombic efficiency reduction, and achieve excellent cycle stability and The effects of rate performance, boost performance, and good cycle performance

Inactive Publication Date: 2018-08-24
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Such a cycle of stress changes will lead to the breakage and pulverization of silicon particles, and will also lead to the inability to form a stable SEI film on the surface of silicon particles, which will eventually lead to a decrease in Coulombic efficiency and a sharp decline in capacity.

Method used

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  • High-performance silicon-carbon composite with core-shell structure, and preparation method and application of silicon-carbon composite in lithium ion battery
  • High-performance silicon-carbon composite with core-shell structure, and preparation method and application of silicon-carbon composite in lithium ion battery
  • High-performance silicon-carbon composite with core-shell structure, and preparation method and application of silicon-carbon composite in lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 1. Silicon powder treatment: Weigh 20g of 500 mesh commercial silicon powder, 200g of zirconium balls (grinding medium), put them into a ball mill pot, add a sealing ring, ball mill at 400rpm for 4 hours, and filter out the obtained micron silicon and zirconium balls through a sieve Zirconium balls are separated and processed to obtain micron silicon powder.

[0039]Two. the preparation of the high-performance silicon-carbon composite material with core-shell structure: take by weighing 7g micron silicon powder, 1g expanded graphite, 0.5g lithium titanate, 0.2g conductive carbon black, 1.3g carbon nanotube and 50g zirconium ball ( Grinding medium) was added into the ball mill jar, and a sealing ring was added, and ball milled at 500rpm for 48 hours, and the obtained sample was filtered through a sieve to remove zirconium balls to obtain a high-performance silicon-carbon composite material with a core-shell structure.

[0040] Take 0.16g of the high-performance silicon-c...

Embodiment 2

[0042] 1. Silicon powder treatment: Weigh 20g of 500 mesh commercial silicon powder, 200g of zirconium balls (grinding medium), put them into a ball mill pot, add a sealing ring, ball mill at 400rpm for 15h, and filter out the obtained micron silicon and zirconium balls through a sieve Zirconium balls are separated and processed to obtain micron silicon powder.

[0043] 2. Preparation of high-performance silicon-carbon composite material with core-shell structure: Weigh 6.31g of micron silicon powder, 1.75g ​​of expanded graphite, 0.3g of lithium titanate, 0.1g of conductive carbon black, 1.54g of carbon nanotubes and 100g of zirconium Put the balls (milling medium) into the ball mill jar, add a sealing ring, and mill at 400rpm for 20h, filter the obtained samples through a sieve to remove the zirconium balls, and obtain a high-performance silicon-carbon composite material with a core-shell structure.

[0044] Take 0.16g of the high-performance silicon-carbon composite materia...

Embodiment 3

[0046] 1. Silicon powder treatment: Weigh 20g of 500 mesh commercial silicon powder, 200g of zirconium balls (grinding medium), put them into a ball mill pot, add a sealing ring, ball mill at 400rpm for 28 hours, and filter out the obtained micron silicon and zirconium balls through a sieve Zirconium balls are separated and processed to obtain micron silicon powder.

[0047] 2. Preparation of high-performance silicon-carbon composite material with core-shell structure: Weigh 5.54g of micron silicon powder, 3g of expanded graphite, 0.1g of lithium titanate, 0.06g of conductive carbon black, 1.3g of carbon nanotubes and 150g of zirconium balls (Grinding medium) was added into the ball mill jar, added with a sealing ring, ball milled at 800rpm for 40h, and the obtained sample was filtered through a sieve to remove zirconium balls to obtain a high-performance silicon-carbon composite material with a core-shell structure.

[0048] Take 0.16g of the high-performance silicon-carbon c...

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Abstract

The invention discloses a high-performance silicon-carbon composite with a core-shell structure, and a preparation method and an application of the silicon-carbon composite in a lithium ion battery, and belongs to the technical field of lithium ion battery materials. The preparation method comprises the steps of ball-milling large particle silicon powder, mixing the treated silicon powder, a compound of lithium oxide and titanium oxide, graphitized carbon black, expanded graphite and a carbon nano tube for ball-milling, and separating a zirconium ball at last to form the silicon-carbon composite. A micron silicon particle serves as a core part; the expanded graphite serves as a shell part to coat the silicon particle and mainly exerts effects of conducting electricity and inhibiting volumeexpansion of silicon; the graphitized carbon black and the carbon nano tube serve as a conduction agent to improve conductivity of the composite; and the compound of the lithium oxide and titanium oxide has the characteristic of zero stress and exerts a support effect on the whole core-shell structure. The composite can serve as a cathode material of the lithium ion battery in the high-power field of new energy electromobiles and the like and has higher specific capacity, good long-period cycle performance and excellent rate capability.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery negative electrode materials, and in particular relates to a high-performance silicon-carbon composite material with a core-shell structure, a preparation method thereof, and an application in lithium-ion batteries. Background technique [0002] In the 21st century, due to the increasingly prominent energy and environmental issues, people urgently need to find a new energy to replace the gradually depleted fossil energy. Since the commercial application of lithium-ion batteries in the 1990s, it has gradually become the leader of energy solutions in the field of IT equipment. Due to its high energy density and mature commercial application model, lithium-ion batteries are regarded as the "No. 1 seed" to replace fossil energy. Especially in recent years, the rise of the field of new energy electric vehicles has put forward higher energy density and higher safety requirements for lithium...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/021H01M2004/027Y02E60/10
Inventor 吴松平夏琪刘淳廖婵杜丽
Owner SOUTH CHINA UNIV OF TECH
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