CN-122000341-A - Electrode material and preparation method thereof, electrode plate and preparation method thereof, and lithium ion battery

CN122000341ACN 122000341 ACN122000341 ACN 122000341ACN-122000341-A

Abstract

The invention discloses an electrode material and a preparation method thereof, wherein the preparation method comprises the steps of providing initial carbon matrix powder, carrying out silicon embedded treatment on the initial carbon matrix powder to obtain carbon-silicon composite powder, wherein the carbon-silicon composite powder comprises a plurality of carbon-silicon composite particles, the carbon-silicon composite particles comprise the initial carbon matrix particles formed with nano silicon, and carrying out titanium coating treatment on the carbon-silicon composite powder to obtain the electrode material, wherein the electrode material comprises a plurality of electrode material particles, and the electrode material particles comprise carbon-silicon composite particles and TiSi 2 protective shells coated on the carbon-silicon composite particles. The invention also discloses an electrode, a preparation method thereof and a lithium ion battery.

Inventors

GUO TIANREN
SUN ZHIQIANG
YU WEIZHAO
CHEN SHENG
Huang Zhuochun

Assignees

浙江方泰思克科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260409

Claims (13)

1. A method for preparing an electrode material, the method comprising: providing an initial carbon matrix powder comprising initial carbon matrix particles, wherein the initial carbon matrix particles have a porous structure; Performing silicon embedded treatment on the initial carbon matrix powder to obtain carbon-silicon composite powder, wherein the carbon-silicon composite powder comprises a plurality of carbon-silicon composite particles, and the carbon-silicon composite particles comprise the initial carbon matrix particles with nano silicon formed thereon; And carrying out titanium coating treatment on the carbon-silicon composite powder to obtain an electrode material, wherein the electrode material comprises a plurality of electrode material particles, and the electrode material particles comprise carbon-silicon composite particles and TiSi 2 protective shells coated on the carbon-silicon composite particles.
2. The method according to claim 1, wherein the subjecting the initial carbon matrix powder to a silicon-embedded treatment to obtain a carbon-silicon composite powder comprises: a silicon source gas is introduced into a process chamber containing the initial carbon matrix powder.
3. The method of claim 2, wherein the step of introducing a silicon source gas into the process chamber containing the initial carbon matrix powder comprises: fluidizing the initial carbon matrix powder with an inert gas at a first temperature within the reactor, the first temperature being between 450 ℃ and 600 ℃; and introducing mixed gas to the reactor for reaction, wherein the mixed gas comprises silane and inert gas, the introducing time is between 0.5 and 5 hours, and the silane accounts for 3 to 7 percent of the volume of the mixed gas.
4. The method according to claim 1, wherein the titanium coating treatment is performed on the carbon-silicon composite powder to obtain an electrode material, comprising: Introducing a titanium source gas and a silicon source gas into a process chamber containing the carbon-silicon composite powder at a set temperature; And cooling and collecting the carbon-silicon composite powder in a process chamber to obtain the electrode material.
5. The method of claim 4, wherein in the step of introducing a titanium source gas and a silicon source gas into the process chamber containing the carbon-silicon composite powder, the partial pressure ratio of the titanium source gas to the silicon source gas is between 1:1 and 1:3, the set temperature is between 500 ℃ and 700 ℃, and the introduction time is between 0.5 hours and 5 hours.
6. The method of claim 4, wherein in the step of introducing the titanium source gas and the silicon source gas into the process chamber containing the carbon-silicon composite powder, the predetermined thickness D of the protective shell of TiSi 2 satisfies d=g×t, where G is a TiSi 2 effective film thickness growth rate and t is a reaction time, and the TiSi 2 effective film thickness growth rate satisfies the following relationship: Where r is the deposition flux, M is the molar mass of the TiSi 2 protective shell, ρ is the density of the TiSi 2 protective shell, and the deposition flux r is determined by the surface coverage and the surface reaction rate of the titanium source gas and the silicon source gas on the carbon-silicon composite particles at a set temperature.
7. The method of claim 6, wherein the deposition flux r satisfies the relationship: Wherein k is the surface reaction rate constant, K0 is a surface reaction factor, ea is the surface reaction activation energy of the titanium source gas and the silicon source gas, R is a gas constant, and T is a reaction temperature; θ Ti is the surface coverage of the titanium source gas on the carbon-silicon composite particles, And theta Si is the surface coverage of the silicon source gas on the carbon-silicon composite particles, P Ti is the partial pressure of the titanium source gas, P Si is the partial pressure of the silicon source gas, K Ti is the adsorption constant of the titanium source gas, K Si is the adsorption constant of the silicon source gas, , K Ti,0 is the adsorption constant of the titanium source gas, deltaH ads,Ti is the adsorption heat of the titanium source gas, K Si,0 is the adsorption constant of the silicon source gas, deltaH ads,Si is the adsorption heat of the silicon source gas.
8. The method of any one of claims 1 to 7, wherein providing an initial carbon matrix powder comprises: heating an initial carbon matrix powder to between 800 ℃ and 1000 ℃, wherein the initial carbon matrix powder comprises at least one of artificial graphite, natural graphite, hard carbon, soft carbon, graphene and carbon nanotubes.
9. An electrode material, characterized in that the electrode material is prepared by the preparation method according to any one of claims 1 to 8.
10. The electrode material of claim 9, wherein the thickness of the protective shell of TiSi 2 is between 2 nm and 50 nm.
11. A method for preparing an electrode sheet, which is characterized in that the electrode material according to any one of claims 9 or 10 is adopted, and the electrode material, a conductive agent, a binder and a solvent are mixed and prepared to obtain electrode slurry; coating the electrode slurry on a metal foil and drying to obtain an initial pole piece; and performing tabletting and punching treatment on the initial electrode plate to obtain the electrode plate.
12. An electrode sheet, characterized in that the electrode sheet is prepared by the preparation method of claim 11.
13. A lithium ion battery comprising a positive electrode, a negative electrode, and a separator and an electrolyte disposed between the positive electrode and the negative electrode, wherein the negative electrode employs the electrode tab of claim 12.

Description

Electrode material and preparation method thereof, electrode plate and preparation method thereof, and lithium ion battery Technical Field The invention relates to the technical field of lithium ion battery materials, in particular to an electrode material and a preparation method thereof, an electrode plate and a preparation method thereof, and a lithium ion battery. Background With the popularization of electric automobiles, large-scale energy storage electronic devices, and portable electronic devices, higher demands are being placed on the energy density of lithium ion batteries. Silicon-based materials are regarded as the most potential negative electrode materials of next-generation high-energy-density lithium ion batteries due to extremely high theoretical specific capacity and abundant natural reserves. However, electrode structures made of silicon-based materials are prone to collapse and eventually lead to dramatic capacity decay. How to improve the stability of an electrode structure made of a silicon-based material is a technical problem to be solved in the art. Disclosure of Invention The present invention aims to solve one of the technical problems in the related art to a certain extent. Therefore, the invention provides an electrode material and a preparation method thereof, an electrode plate and a preparation method thereof, and a lithium ion battery. As a first aspect of the present invention, there is disclosed a method for producing an electrode material, the method comprising: providing an initial carbon matrix powder comprising initial carbon matrix particles, wherein the initial carbon matrix particles have a porous structure; Performing silicon embedded treatment on the initial carbon matrix powder to obtain carbon-silicon composite powder, wherein the carbon-silicon composite powder comprises a plurality of carbon-silicon composite particles, and the carbon-silicon composite particles comprise the initial carbon matrix particles with nano silicon formed thereon; And carrying out titanium coating treatment on the carbon-silicon composite powder to obtain an electrode material, wherein the electrode material comprises a plurality of electrode material particles, and the electrode material particles comprise carbon-silicon composite particles and TiSi 2 protective shells coated on the carbon-silicon composite particles. Further, the initial carbon matrix powder is subjected to silicon embedded treatment to obtain carbon-silicon composite powder, and the method comprises the step of introducing silicon source gas into a process chamber containing the initial carbon matrix powder. Further, the step of introducing a silicon source gas into the process chamber containing the initial carbon matrix powder comprises: fluidizing the initial carbon matrix with an inert gas at a first temperature within the reactor, the first temperature being between 450 ℃ and 600 ℃; and introducing mixed gas to the reactor for reaction, wherein the mixed gas comprises silane and inert gas, the introducing time is between 0.5 and 5 hours, and the silane accounts for 3 to 7 percent of the volume of the mixed gas. Further, the process of coating the carbon-silicon composite powder with titanium to obtain an electrode material includes: And introducing titanium source gas and silicon source gas into the process chamber containing the carbon-silicon composite powder at a set temperature, and cooling and collecting the carbon-silicon composite powder in the process chamber to obtain the electrode material. Further, in the step of introducing the titanium source gas and the silicon source gas into the process chamber containing the carbon-silicon composite powder, the partial pressure ratio of the titanium source gas to the silicon source gas is between 1:1 and 1:3, the set temperature is between 500 ℃ and 700 ℃, and the introducing time is between 0.5 hours and 5 hours. Further, in the step of introducing the titanium source gas and the silicon source gas into the process chamber containing the carbon-silicon composite powder, the preset thickness D of the TiSi 2 protective shell satisfies d=g×t, where G is an effective film thickness growth rate, and t is a reaction time, and the effective film thickness growth rate satisfies the following relationship: Where r is the deposition flux, M is the molar mass of the TiSi 2 protective shell, ρ is the density of the TiSi 2 protective shell, and the deposition flux r is determined by the surface coverage and the surface reaction rate of the titanium source gas and the silicon source gas on the carbon-silicon composite particles at a set temperature. Further, the deposition flux r satisfies the following relationship: Wherein k is the surface reaction rate constant, K0 is a surface reaction factor, ea is the surface reaction activation energy of the titanium source gas and the silicon source gas, R is a gas constant, and T is a reaction temperature; θ Ti is the surface cove