A multi-component composite high-first-efficiency lithium battery negative electrode material and preparation method thereof

A multi-component composite and negative electrode material technology, applied in the direction of battery electrodes, negative electrodes, secondary batteries, etc., can solve the problems of reduced initial charge/discharge efficiency, unstable slurry, and increased irreversible capacity, so as to improve Coulombic efficiency and cycle The performance, the preparation method are simple and easy, and the effect of being convenient for large-scale production

Active Publication Date: 2022-03-15
LANXI ZHIDE ADVANCED MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the initial charge of silicon oxide, lithium reacts with silicon oxide to produce lithium oxide (including lithium oxide and lithium silicate, etc.), and the produced lithium oxide cannot reversibly return to the positive electrode during discharge, making irreversible Increased capacity, significantly reduced initial charge / discharge efficiency (ICE)
[0004] In order to improve the initial charge / discharge efficiency of silicon oxide (SiOx), the patent CN201480059867.2 prepared Li-doped Si / SiO by electrochemical method x material, which improves the first charge and discharge efficiency, but there are still problems such as capacity reduction and slurry instability; patent application CN201710193442.6 passed SiO x Mg-doped Si / SiO was prepared by reacting with metallic magnesium x material, the efficiency has been greatly improved for the first time, but the silicon grain size is too large due to the addition of Mg, and the process is not easy to control, resulting in poor cycle performance of the material

Method used

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  • A multi-component composite high-first-efficiency lithium battery negative electrode material and preparation method thereof
  • A multi-component composite high-first-efficiency lithium battery negative electrode material and preparation method thereof
  • A multi-component composite high-first-efficiency lithium battery negative electrode material and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] A certain amount of Si powder, SiO 2 Powder and metal magnesium powder are evenly mixed and added to a vacuum furnace for heat treatment. Heated to 1100°C under the condition of 500Pa vacuum degree, and the heat treatment time was 1h. The above powder is sublimated under high temperature and vacuum conditions, and the silicon oxide precursor uniformly doped with magnesium is obtained after the steam is condensed. Then crush and sieve to obtain particles with a particle size of 1-10um.

[0041] The particles obtained above were loaded into a CVD furnace, and propylene with a flow rate of 9 L / min and argon gas with a flow rate of 18 L / min were fed in for a deposition time of 1 h. Propylene is cracked at high temperature, pyrolytic carbon is coated on the particle surface, and a carbon-coated magnesium-doped SiO composite powder is obtained, and the thickness of the carbon coating layer is 80nm. Mix the composite powder obtained above with a certain amount of Li3N powde...

Embodiment 2

[0044] Lithium and magnesium co-doping are performed simultaneously using a multi-deposition chamber CVD furnace. Put a certain amount of Si powder and SiO powder with median diameter D50=5μm mixed uniformly in the deposition chamber 1 respectively. 2 powder, put a certain amount of magnesium powder in the deposition chamber 2, and put a certain amount of LiCl powder in the deposition chamber 3. Deposition chamber 1 is heated to 1100°C to make Si and SiO 2 sublimation. The deposition chamber 2 is heated to 1100°C to sublimate the Mg powder. The deposition chamber 3 is heated to 950° C. to vaporize LiCl. The three deposition chambers were all evacuated, the vacuum degree was controlled at 100 Pa, and the reaction time was controlled at 1 h. Then the gasified LiCl vapor, SiO vapor and Mg vapor were co-deposited in the collection chamber to obtain magnesium and lithium co-doped SiO composite powder. Then crush and sieve to obtain particles with a particle size of 1-10um.

[...

Embodiment 3~10

[0048] Other steps are identical with embodiment 1 with process parameter, difference is that Si powder that adds, SiO 2 Powder, metal magnesium powder and Li3N powder are different in quality, change the molar ratio of lithium atoms to magnesium atoms, and the content of lithium silicate and magnesium silicate.

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Abstract

The invention relates to a multi-component composite high-first-efficiency lithium battery negative electrode material and a preparation method thereof. The negative electrode material is co-doped with Li and Mg to form SiO x ‑Lithium silicate‑magnesium silicate multiple composite system. The negative electrode material includes silicon compound particles and a conductive layer coated on the surface of the silicon compound particles, the negative electrode material also includes lithium silicate, magnesium silicate, lithium atoms in the lithium silicate and the magnesium silicon The molar ratio of magnesium atoms in the acid salt is 0.01:1~100:1. The invention combines the characteristics of the high ion conductivity of the lithium silicate and the high bonding strength of the magnesium silicate, further improves the first coulombic efficiency of the material and improves the cycle life at the same time.

Description

technical field [0001] The invention relates to the field of lithium battery materials, in particular to a multi-element composite lithium battery negative electrode material and a preparation method thereof. Background technique [0002] Due to its high theoretical specific capacity (4200 mA h / g at high temperature and 3580 mA h / g at room temperature), low delithiation potential (<0.5 V), silicon anode material is environmentally friendly, abundant in reserves, and low in cost. It is considered to be a very potential next-generation high-energy-density lithium-ion battery anode material due to its advantages. However, the electrical conductivity of silicon itself is low, and the volume change is large (about 300%) during the lithium-deintercalation process, so that the material is easily pulverized gradually, causing the structure to collapse, and eventually the electrode active material is separated from the current collector, and the electrical contact is lost. , resu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/58H01M4/62H01M10/0525
CPCH01M4/366H01M4/483H01M4/5825H01M4/625H01M10/0525H01M2004/027Y02E60/10
Inventor 胡盼刘江平肖旦陈青华房冰
Owner LANXI ZHIDE ADVANCED MATERIALS CO LTD
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