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Silicon-based si-c negative electrode material prepared based on silicon-based oxide and its preparation method and application

A technology of silicon-based oxides and negative electrode materials, applied in the direction of negative electrodes, carbon compounds, active material electrodes, etc., can solve the problems of uneven distribution of silicon and carbon, easy agglomeration of silicon particles, and high production costs, so as to improve electrochemical performance, Moderate silicon particle size, the effect of improving electrical conductivity

Active Publication Date: 2021-02-19
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The amorphous carbon formed after calcination isolates the contact between silicon and electrolyte and improves the stability of the material, but there are still problems such as uneven distribution of silicon and carbon, easy agglomeration of silicon particles, insufficient conductivity, and easy ohmic polarization.
At the same time, the preparation process of the above-mentioned silicon-carbon composite materials is complicated and the production cost is high.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] A method for preparing a silicon-based Si-C negative electrode material prepared based on a silicon-based oxide is carried out in the following steps;

[0047] (1) Place calcium chloride and sodium chloride salts in a vacuum oven at 300°C for 12 hours to remove water.

[0048] (2) Under argon protection, weigh 2.5±0.1g of calcium silicate, 2.8±0.1g of calcium carbide, 88.8±0.1g of calcium chloride, 44.4±0.1g of sodium chloride in a ceramic mortar Grind, mix, put into a ziplock bag and seal.

[0049](3) Pour the mixed salt into the nickel crucible embedded in the reactor, and seal it;

[0050] (4) Argon gas is introduced from the reactor inlet, and argon gas is discharged from the reactor gas outlet to ensure positive pressure in the reactor, and the resistance wire furnace is heated at a rate of 5° C. / min.

[0051] (5) Raise the temperature to 590°C and keep the temperature constant for 5 hours to melt the molten salt and promote the reaction. Raise the temperature o...

Embodiment 2

[0062] A method for preparing a silicon-based Si-C negative electrode material prepared based on a silicon-based oxide is the same as in Example 1, except that:

[0063] (1) In step (1), the molten salt is replaced with 88.8g calcium chloride, 178.8g potassium chloride;

[0064] (2) In step (5), the synthesis temperature is 650°C;

[0065] Other methods are the same.

[0066] Prepare silicon-based Si-C negative electrode materials based on silicon-based oxides with a particle size of 15 to 45 microns, and use the prepared silicon-based Si-C negative electrode materials based on silicon-based oxides as negative electrode materials for lithium-ion batteries , the lithium-ion battery prepared by the method of Application Example 1 has a specific discharge capacity of 2987.5mAh·g for the first time -1 , Coulombic efficiency is 79%, at 0.2A·g -1 After 400 cycles of current density, the reversible cycle specific capacity of the battery is 1385.6mAh g -1 , the Coulombic efficienc...

Embodiment 3

[0068] A method for preparing a silicon-based Si-C negative electrode material prepared based on a silicon-based oxide is the same as in Example 1, except that:

[0069] (1) In step (1), the molten salt is replaced with 88.8g calcium chloride, 178.8g potassium chloride, 44.4g sodium chloride;

[0070] (2) In step (5), the synthesis temperature is 630°C;

[0071] Other methods are the same.

[0072] Prepare silicon-based Si-C negative electrode materials based on silicon-based oxides with a particle size of 10-30 microns, and use the prepared silicon-based Si-C negative electrode materials based on silicon-based oxides as negative electrode materials for lithium-ion batteries , the first discharge specific capacity of the lithium-ion battery prepared by the method of Application Example 1 is 2790.5mAh g -1 , Coulombic efficiency is 80.5%, at 0.2A g -1 After 400 cycles of current density, the reversible cycle specific capacity of the battery is 1302.8mAh g -1 , the Coulombic...

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Abstract

A silicon-based Si-C negative electrode material prepared on the basis of silicon-based oxide, its preparation method and application, belong to the field of battery negative electrode material preparation. The silicon-based Si-C negative electrode material prepared based on silicon-based oxides uses silicon-based oxides and calcium carbide as raw materials, reacts in calcium chloride-based molten salts to prepare silicon-based Si-C negative electrode materials, and prepares the negative electrode The material is used to prepare the negative electrode of the lithium ion battery, and the prepared lithium ion battery has good specific capacity and cycle performance. By adjusting the salt composition and ratio, synthesis temperature, synthesis time, stirring rate and stirring time, the reaction between silicon-based oxides and calcium carbide and the production process of silicon-based Si-C negative electrode materials prepared based on silicon-based oxides are regulated. Control the reaction rate, promote the uniform distribution of silicon and carbon in the Si-C product and control the particle size, which is beneficial to effectively buffer the volume expansion of the silicon-lithium alloying process as the negative electrode material of lithium-ion batteries, improve the conductivity of silicon materials, and improve the electrochemical performance .

Description

technical field [0001] The invention relates to the field of preparation of negative electrode materials for batteries, in particular to a silicon-based Si-C negative electrode material prepared based on silicon-based oxides and its preparation method and application. Background technique [0002] With the increasing use of portable electronic devices and electric vehicles, the development of lithium-ion batteries with high energy density has become an urgent need. Graphite is the current commercial lithium-ion battery anode material, and its theoretical capacity is 372mAh / g, which cannot meet the high-capacity demand of the next-generation lithium-ion battery. Therefore, it is urgent to develop a high-capacity, high-power-density anode material to replace graphite. As the anode material of lithium-ion batteries, silicon has attracted much attention because of its theoretical capacity as high as 4200mAh / g, abundant reserves, low price, and low intercalation / delithiation pot...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/963H01M4/36H01M4/38H01M4/587H01M10/0525
CPCC01P2006/40C01B32/963H01M4/364H01M4/386H01M4/587H01M10/0525H01M2004/027Y02E60/10
Inventor 谢宏伟徐亚男王锦霞尹华意宋秋实宁志强
Owner NORTHEASTERN UNIV