Silicon/silicon oxide-titanium dioxide-carbon core-shell structure composite particle and preparation thereof

A technology of composite particles and silicon oxide, which is applied in the direction of structural parts, secondary batteries, electrochemical generators, etc., can solve problems such as difficulty in ensuring coating uniformity, and achieve easy batch preparation, high specific capacity, uniform and dense crystallization degree of effect

Active Publication Date: 2019-05-28
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing coating methods mainly have the following problems: 1) The coating method mainly focuses on the liquid phase method, adding precursors for solvothermal or hydrolysis reactions to deposit on the surface of the powder, and then obtaining the coating structure by high temperature treatment
It can not only solve the problem that the coating uniformity of the existing liquid phase method is difficult to guarantee, but also is more oriented to actual production and is suitable for industrial scale-up. It has continuous mass production capacity and improves efficiency while preparing products with excellent electrochemical performance.

Method used

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  • Silicon/silicon oxide-titanium dioxide-carbon core-shell structure composite particle and preparation thereof
  • Silicon/silicon oxide-titanium dioxide-carbon core-shell structure composite particle and preparation thereof
  • Silicon/silicon oxide-titanium dioxide-carbon core-shell structure composite particle and preparation thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0073] 100gSiO x The powder is placed in the fluidized bed reactor, with 600h -1 The space velocity of the Ar gas is introduced to make the powder in a fully fluidized state, and then the temperature is raised to 1200°C at a rate of 15°C / min; the TiCl carried by Ar is 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:6 is respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:5,H 2 O:Ar=1:10, the total space velocity of the two gases is 600h -1 . Stop feeding TiCl after 40min 4 steam and water vapor, naturally cooled to room temperature, the intermediate product SiO x @TiO 2 .

[0074] The intermediate product SiO x @TiO 2 Placed in a fluidized bed reactor for 600h -1 Inject Ar gas at a space velocity to keep the powder in a fully fluidized state, and then raise the temperature to 850°C at a rate of 10°C / min; 2 h 4 The gas is introduced into the fluidized bed for deposition reaction, where C 2 h 4 :Ar=1:6, the tota...

Embodiment 2

[0081] 100gSiO x The powder is placed in the fluidized bed reactor, with 200h -1 The space velocity of the Ar gas is introduced to make the powder in a fully fluidized state, and then the temperature is raised to 1000°C at a rate of 5°C / min; the TiCl carried by Ar is 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:2 is respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:1,H 2 O: Ar = 1: 2, the total space velocity of the two gases is 200h -1 . Stop feeding TiCl after 10min 4 steam and water vapor, naturally cooled to room temperature, the intermediate product SiO x @TiO 2 .

[0082] The intermediate product SiO x @TiO 2 Placed in a fluidized bed reactor for 200h -1 The space velocity of the Ar gas is introduced to make the powder in a fully fluidized state, and then the temperature is raised to 700°C at a rate of 5°C / min; the C carried by Ar is 3 h 6 The gas is introduced into the fluidized bed for deposition re...

Embodiment 3

[0084] 100gSiO x The powder is placed in the fluidized bed reactor, with 1000h -1 The space velocity of the Ar gas is introduced to make the powder in a fully fluidized state, and then the temperature is raised to 1400°C at a rate of 15°C / min; the TiCl carried by Ar is 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:10 is respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:10,H 2 O:Ar=1:20, the total space velocity of the two gases is 1000h -1 . Stop feeding TiCl after 60min 4 steam and water vapor, naturally cooled to room temperature, the intermediate product SiO x @TiO 2 .

[0085]The intermediate product SiO x @TiO 2 placed in a fluidized bed reactor for 1000h -1 Inject Ar gas at a space velocity to keep the powder in a fully fluidized state, and then raise the temperature to 1000°C at a rate of 15°C / min; 2 h 2 The gas is introduced into the fluidized bed for deposition reaction, where C 2 h 2 :Ar=1:10, th...

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Abstract

The invention discloses a silicon/silicon oxide-titanium dioxide-carbon core-shell structure composite particle, and belongs to the field of lithium ion battery negative electrode materials. The composite particle is of a compact three-layer structure and comprises a core, a middle layer and an outer layer, wherein the core contains silicon or an oxide thereof, the middle layer contains titanium dioxide TiO2, and the outer layer is a carbon-containing C layer. In addition, the invention also provides a preparation method of the composite particle, comprising a titanium coating step and a carbon coating step, wherein the titanium coating step and the carbon coating step are both completed in a fluidized bed reactor. The core-shell structure composite particle prepared by the preparation method disclosed by the invention is high in specific capacity and has excellent cycling stability and rate capability.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery negative electrode materials, in particular to silicon or its oxide@titanium dioxide@carbon core-shell structure composite particles and a preparation method, which can be used for lithium-ion battery negative electrode materials. Background technique [0002] Since the advent of lithium-ion batteries, they have been widely used in many fields because of their high energy density, high power density, low self-discharge, and high safety. In recent years, the development of high-capacity-density lithium-ion batteries has become an important goal in the future. As a representative of the anode material of a new generation of lithium-ion batteries, silicon has a wide range of sources, low cost, the highest theoretical specific capacity (4200mAh / g), and large volumetric energy density (9786mAh / cm 3 ) and other characteristics, and the delithiation potential of silicon compounds in the elec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/485H01M4/62H01M10/0525
CPCY02E60/10
Inventor 肖哲熙魏飞张晨曦于春辉林贤清
Owner TSINGHUA UNIV
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