Anode material, preparation method thereof and lithium ion battery

Patent metadata

Field	Value
Publication number	US-2025132315-A1
Application number	US-202318690131-A
Country	US
Kind code	A1
Filing date	Sep 28, 2023
Priority date	Dec 28, 2022
Publication date	Apr 24, 2025
Grant date	—

Abstract

The present disclosure discloses an anode material and a preparation method and application thereof, the anode material includes a core and a coating layer located on at least part of the surface of the core, the core includes a silicon oxide material, the anode material contains a lithium element, and a mass ratio of the lithium element to the oxygen element in the anode material is a; the anode material is tested through an X-ray photoelectron spectroscopy (Thermo Scientific K-Alpha), a mass ratio of the lithium element to the oxygen element in the region corresponding to the information detectable in the detection process from the surface of the anode material to the inner center region of the anode material is b, a relationship between a and b satisfies 0.4>a>b, the ratio of the lithium element to the oxygen element on the surface layer of the anode material is controlled to be smaller than the ratio of the overall lithium element to the oxygen element of the material, so that the lithium element is more present in the inner center region of the material, the corrosion effect of a water solvent on Si crystal grains in the inner center region of the silicon oxide material is weakened by reducing the content of the lithium element on the surface, and the slurry processing stability is improved.

First claim

1 . An anode material, comprising a core and a coating layer located on at least part of a surface of the core, wherein the core comprises a silicon oxide material, and the anode material contains a lithium element;
a mass ratio of lithium element to oxygen element in the anode material is represented as a, and a mass ratio of lithium element to oxygen element in a region corresponding to information detected by an X-ray photoelectron spectroscopy during a detection process from a surface of the anode material to an inner central region of the anode material is represented as b, and a relationship between a and b satisfies 0.4>a>b.

2 . The anode material according to claim 1 , comprising at least one of the following features (1) to (7):
(1) a mass ratio a of lithium element to oxygen element in the anode material satisfies 0.35>a>0.15; (2) b satisfies 0.30>b>0.01; (3) a thickness of the region corresponding to information detected by an X-ray photoelectron spectroscopy (Thermo Scientific K-Alpha) during a detection process from a surface of the anode material to an inner central region of the anode material ranges from 1 nm to 10 nm. (4) the silicon oxide material includes SiO x , where 0<x≤2; (5) the silicon oxide material includes a lithium-containing compound, and the lithium-containing compound comprises at least one of Li 2 SiO 3 , Li 2 Si 2 O 5 , and Li 4 SiO 4 . (6) based on 100% of a mass of the anode material, the mass ratio of the lithium element in the anode material ranges from 1 wt % to 15 wt %; (7) a molar ratio of Si element to O element in the anode material is (0.8 to 1.2): 1.

3 . The anode material according to claim 1 , comprising a first coating layer and a second coating layer, wherein
the second coating layer is located between the core and the first coating layer, and/or the second coating layer is located on a region of the core surface that is not coated by the first coating layer.

4 . The anode material according to claim 3 , comprising at least one of the following features (1) to (6):
(1) the second coating layer comprises at least one of a phosphate compound of silicon, a phosphate compound of aluminum, a phosphate compound of ammonium, and an aluminum-phosphorus composite oxide; (2) a material of the first coating layer comprises a carbon material; (3) a mass ratio of the first coating layer in the anode material ranges from 0.1% to 5%; (4) a mass ratio of the second coating layer in the anode material ranges from 0.1% to 8%; (5) a thickness of the first coating layer ranges from 1 nm to 1000 nm; (6) a thickness of the second coating layer ranges from 1 nm to 1000 nm.

5 . The anode material according to claim 1 , comprising at least one of the following features (1) to (2):
(1) the coating layer is a carbon layer; (2) a thickness of the coating layer ranges from 1 nm to 1000 nm.

6 . The anode material according to claim 1 , comprising at least one of the following features (1) to (5):
(1) a pore volume of the anode material is smaller than 0.01 cm 3 /g; (2) a specific surface area of the anode material is smaller than 4 m 2 /g; (3) a contact angle θ of the anode material to acetone was tested by a Washburn method, wherein θ>20°; (4) a pH value of the anode material satisfies 7<pH<11.5; (5) a median particle size of the anode material ranges from 3.0 μm to 10.0 μm.

7 . A method for preparing an anode material, comprising the following steps:
pre-lithiating the silicon-oxygen raw material to obtain a pre-lithiated material, wherein, a mass ratio of the lithium element to the silicon-oxygen raw material in the pre-lithiated material is (0.02 to 0.16): 1; subjecting a mixture containing the pre-lithiated material and polycarboxylic acid to a first heat treatment to cure the mixture to obtain a precursor; performing a second heat treatment on the precursor to carbonize the precursor to obtain an anode material.

8 . The method according to claim 7 , comprising at least one of the following features (1) to (13):
(1) a temperature of the first heat treatment is 150° C. to 250° C.; (2) time of the first heat treatment is 5 h to 12 h; (3) the first heat treatment is performed in an air atmosphere; (4) before performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method further comprises: drying the mixture containing the pre-lithiated material and polycarboxylic acid; (5) before performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method further comprises: drying the mixture containing the pre-lithiated material and polycarboxylic acid at a temperature of 45° C. to 90° C.; (6) after performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method further comprises: washing, solid-liquid separating and drying a material obtained by the first heat treatment to obtain a precursor; (7) after performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method further comprises: washing, solid-liquid separating and drying a material obtained by the first heat treatment, the solvent for washing comprises at least one of water and ethanol; (8) after performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method further comprises: washing, solid-liquid separation and drying a material obtained by the first heat treatment, the solid-liquid mass ratio of the washing is (1 to 4): 1; (9) after performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method comprises: washing, solid-liquid separation and drying a material obtained by the first heat treatment, the washing time is 1 h to 5 h; (10) after performing the first heat treatment on the mixture containing the pre-lithiated material and the polycarboxylic acid, the method comprises: washing, solid-liquid separating and drying a material obtained by the first heat treatment, the drying temperature is 80° C. to 120° C.; (11) a temperature of the second heat treatment is 500° C. to 800° C.; (12) time of the second heat treatment is 5 h to 12 h; (13) the second heat treatment is performed in a protective gas atmosphere.

9 . The method according to claim 7 , wherein, the mixture containing the pre-lithiated material and the polycarboxylic acid is prepared by: placing the polycarboxylic acid in a solvent to obtain a carbon source solution containing polycarboxylic acid, and mixing the pre-lithiated material and the carbon source solution containing polycarboxylic acid to obtain a mixture containing the pre-lithiated material and polycarboxylic acid.

10 . The method according to claim 9 , comprising at least one of the following features (1) to (4):
(1) a concentration of the carbon source solution is 3 mg/mL to 7 mg/mL; (2) the polycarboxylic acid comprises at least one of citric acid, tartaric acid, maleic acid, trimesic acid, terephthalic acid, malic acid and ethylene diaminetetraacetic acid; (3) the solvent comprises at least one of acetone, water, ethanol, methanol, isopropanol, dimethylformamide, toluene and tetrahydrofuran; (4) a mass ratio of the pre-lithiated material to the polycarboxylic acid is (20 to 200): 1.

11 . The method according to claim 7 , wherein, the silicon-oxygen raw material is a silicon-oxygen material having a coating layer, and the silicon-oxygen material having a coating layer is prepared by: providing a silicon oxide material, mixing the silicon oxide material

Assignees

• Btr New Mat Group Co Ltd
• Dingyuan New Energy Tech Co Ltd

Inventors

• Guo Songtao
• Deng Zhiqiang
• Xie Wei
• Li Fangru
• Pang Chunlei
• Ren Jianguo
• He Xueqin

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title