Carbon material, preparation method thereof, and secondary battery and electric apparatus containing the same

Patent metadata

Field	Value
Publication number	US-2025183317-A1
Application number	US-202519047561-A
Country	US
Kind code	A1
Filing date	Feb 6, 2025
Priority date	Nov 25, 2022
Publication date	Jun 5, 2025
Grant date	—

Abstract

This application provides a carbon material, a preparation method thereof, and a secondary battery and electric apparatus containing the same. The carbon material includes a pore structure, and in a thermogravimetric analysis test of the carbon material under air atmosphere, a weight loss rate of the carbon material at 35° C. to 790° C. is less than or equal to 60%. The carbon material provided in this application enables the secondary battery to combine high initial coulombic efficiency and good storage performance.

First claim

What is claimed is:

1 . A carbon material, wherein the carbon material comprises a pore structure, and in a thermogravimetric analysis test of the carbon material under air atmosphere, a weight loss rate of the carbon material at 35° C. to 790° C. is less than or equal to 60%.

2 . The carbon material according to claim 1 , wherein the weight loss rate of the carbon material at 35° C. to 790° C. is 5%-55%, and optionally 15%-45%.

3 . The carbon material according to claim 1 , wherein in the thermogravimetric analysis test of the carbon material under air atmosphere, a maximum weight loss rate of the carbon material is less than or equal to 5.5%/min, and optionally 0.5%/min-5%/min.

4 . The carbon material according to claim 1 , wherein in the thermogravimetric analysis test of the carbon material under air atmosphere, a temperature corresponding to the maximum weight loss rate of the carbon material is denoted as T max , wherein T max is 790° C.-910° C., and optionally 800° C.-850° C.

5 . The carbon material according to claim 1 , wherein in the thermogravimetric analysis test of the carbon material under air atmosphere, an initial weight loss temperature of the carbon material is denoted as T 0 , wherein T 0 is 725° C.-900° C., and optionally 728° C.-785° C.

6 . The carbon material according to claim 1 , wherein the carbon material comprises more than one pore structure with a pore area greater than or equal to 0.1 μm 2 , and optionally comprises more than one pore structure with a pore area of 0.12 μm 2 -1.5 μm 2 .

7 . The carbon material according to claim 1 , wherein the carbon material comprises an exterior zone and an interior zone located inside the exterior zone, wherein the exterior zone is a zone extending from the surface of the carbon material particle to the interior of the particle by a distance of 0.25 L, L refers to a short-axis length of the carbon material particle, a total pore area of the exterior zone is denoted as S 1 , a total pore area of the interior zone is denoted as S 2 , and S 2 >S 1 , optionally 1.5≤S 2 /S 1 ≤400, and 2≤S 2 /S 1 ≤200.

8 . The carbon material according to claim 7 , wherein
0.01 μm 2 ≤S 1 ≤5.5 μm 2 , and optionally, 0.06 μm 2 ≤S 1 ≤4.5 μm 2 ; and/or 2.5 μm 2 ≤S 2 ≤25.0 μm 2 , and optionally, 4.0 μm 2 ≤S 2 ≤15.0 μm 2 ; and/or L≥7 μm, and optionally, 7 μm≤L≤18 μm.

9 . The carbon material according to claim 7 , wherein
an area of the pore structure in the exterior zone of the carbon material is less than 0.2 μm 2 , and optionally less than or equal to 0.12 μm 2 ; and/or the interior zone of the carbon material comprises more than one pore structure with an area greater than or equal to 0.12 μm 2 , and optionally comprises more than one pore structure with an area of 0.12 μm 2 -2.5 μm 2 ; and/or an interlayer spacing in the exterior zone of the carbon material is denoted as d 1 , an interlayer spacing in the interior zone of the carbon material is denoted as d 2 , and the carbon material satisfies d 1 ≥ d 2 ; and optionally, d 1 >d 2 .

10 . The carbon material according to claim 9 , wherein
d 1 is 0.33565 nm-0.33620 nm; and/or d 2 is 0.33557 nm-0.33589 nm.

11 . The carbon material according to claim 1 , wherein the carbon material satisfies at least one of the following:
(1) a specific surface area of the carbon material is 0.7 m 2 /g-1.6 m 2 /g, and optionally 0.8 m 2 /g-1.4 m 2 /g; (2) a particle size by volume D v 50 of the carbon material is 10.0 μm-20.0 μm, and optionally 12.0 μm-18.0 μm; (3) a particle size by volume D v 10 of the carbon material is 4.0 μm-13.0 μm, and optionally 6.0 μm-11.0 μm; (4) a particle size by volume D v 90 of the carbon material is 25.0 μm-35.0 μm, and optionally 27.0 μm-32.0 μm; (5) a particle size distribution (D v 90-D v 10)/D v 50 of the carbon material is 0.90-1.10, and optionally 0.95-1.05; and (6) the carbon material is in one or more of block-shaped, spherical, and spheroidal morphologies.

12 . The carbon material according to claim 1 , wherein the carbon material satisfies at least one of the following:
(1) a tap density of the carbon material is 1.0 g/cm 3 -1.5 g/cm 3 , and optionally 1.1 g/cm 3 -1.4 g/cm 3 ; (2) a gram capacity of the carbon material is 350 mAh/g-372 mAh/g, and optionally 353 mAh/g-371 mAh/g; and (3) a degree of graphitization of the carbon material is 91.5%-98.5%, and optionally 92.5%-98.0%.

13 . A preparation method of carbon material, comprising the following steps: step 1, providing a raw material having a plurality of pore structures; step 2, mixing the raw material with a filling material homogeneously at a predetermined ratio, and leaving the resulting product standing at a first temperature T 1 for a first time t 1 to obtain an intermediate; and step 3, leaving the resulting intermediate standing at a second temperature T 2 for a second time t 2 to obtain a carbon material, wherein the carbon material comprises a pore structure, and in a thermogravimetric analysis test of the carbon material under air atmosphere, a weight loss rate of the carbon material at 35° C. to 790° C. is less than or equal to 60%.

14 . The method according to claim 13 , wherein the raw material satisfies at least one of the following:
(1) the raw material comprises natural graphite, and optionally the natural graphite comprises one or more of flake graphite, natural spherical graphite, and microcrystalline graphite; (2) a particle size by volume D v 50 of the raw material is 10.0 μm-20.0 μm, and optionally 12.0 μm-18.0 μm; and (3) a percentage of element carbon in the raw material is greater than or equal to 90.0 wt %, and optionally greater than or equal to 95.0 wt %.

15 . The method according to claim 13 , wherein the filling material satisfies at least one of the following:
(1) a softening point temperature of the filling material is 80° C.-150° C., and optionally 90° C.-140° C.; (2) a coking value of the filling material is 15%-40%, and optionally 15%-35%; (3) a particle size by volume D v 50 of the filling material is less than or equal to 6 μm, and optionally 2 μm-5 μm; and (4) the filling material comprises one or more of coal asphalt, petroleum asphalt, polymer compounds, and resins, and optionally comprises petroleum asphalt.

16 . The method according to claim 13 , wherein a mass ratio of the filling material to the raw material is (10-35):100, and optionally (15-32):100.

17 . The method according to claim 13 , wherein after the mixing the raw material with a filling material homogeneously at a predetermined ratio, the process of heating up to the first temperature T 1 is a staged heating process, and optionally comprises a first heating process and a second heating process.

18 . The method according to claim 17 , wherein the heating process satisfies at least one of the following:
(1) the first heating process is heating up to 200° C.-250° C. and holding at that temperature for 1 h-3 h; (2) the second heating process is heating to the first temperature T 1 and holding at that temperature for the first time t 1 ; (3) a heating rate of the first heating process is 1° C./min-10° C./min, and optionally 1.5° C./min-8° C./min; (4) a heating rate of the second heating process is 2° C./min-10° C./min, and optionally 2.5° C./min-8° C./min; (5) the first temperature T 1 is 700° C.-1200° C., and optionally 800° C.-1100° C.; (6) the first time t 1 is 1 h-5 h, and optionally 2 h-4 h; (7) the second temperature T 2 is 2000° C.-2700° C., and optionally 2100° C.-2600° C.; (8) the second time t

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Chen Yonghong
• Shen Rui
• He Libing

Classifications

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M10/0525

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

• C01P2006/80

  Compositional purity · CPC title