Granted Patent B2

US 12,463,204 · App. 17/623,303 · Granted Nov 4, 2025

Inventors: Haihui Zhou (Guangdong, CN); Junhui Lai (Guangdong, CN); Tao Xu (Guangdong, CN); Jianguo Ren (Guangdong, CN); Xueqin He (Guangdong, CN)

Assignee: BTR NEW MATERIAL GROUP CO., LTD.

H01M4/366C01B32/21H01M4/587H01M10/0525C01P2002/02C01P2004/03C01P2004/32C01P2004/61C01P2004/84C01P2006/11C01P2006/12C01P2006/40H01M2004/021H01M2004/027

Abstract

Claims (88)

1 . A negative electrode material, wherein the negative electrode material comprises a first graphite core and a composite coating layer coated on the first graphite core, and the composite coating layer comprises a second graphite inner layer located on a surface of the first graphite core and an amorphous carbon outer layer located on a surface of the second graphite inner layer, and the second graphite inner layer comprises a plurality of graphite microcrystals, wherein a ratio of the median particle diameter of the first graphite core to a median particle diameter of the graphite microcrystal is 5:1-50:1.

2 . The negative electrode material according to claim 1 , wherein the first graphite core satisfies at least one of following conditions a to e:

a. the first graphite core comprises natural graphite;

b. the first graphite core is spherical natural graphite;

c. the first graphite core has a median particle diameter of 2.0 μm-30.0 μm;

d. the natural graphite has a powder-body tap density of 0.4 g/cm 3 -1.0 g/cm 3 ; and

e. a mass percentage content of fixed carbon in the natural graphite is ≥99.9%.

3 . The negative electrode material according to claim 1 , wherein the graphite microcrystal satisfies at least one of following conditions a to d:

a. the graphite microcrystal is at least partially embedded in the first graphite core;

b. the median particle diameter of the graphite microcrystal is 0 μm-2 μm, not including 0 μm;

c. a fixed carbon content of the graphite microcrystal is ≥99.9%; and

d. a powder-body tap density of the graphite microcrystal is 0 g/cm 3 -0.5 g/cm 3 , not including 0 g/cm 3 .

4 . The negative electrode material according to claim 1 , wherein the negative electrode material satisfies at least one of following conditions a-e:

a. a median particle diameter of the negative electrode material is 2 μm-32 μm, not including 2 μm;

b. the negative electrode material has a specific surface area of 0.5 m 2 /g-20.0 m 2 /g;

c. a powder-body tap density of the negative electrode material is 0.5 g/cm 3 -1.3 g/cm 3 ;

d. the composite coating layer has a thickness of 0 μm-5 μm, not including 0 μm; and

e. the amorphous carbon outer layer has a thickness of 0 nm-500 nm, not including 0 nm.

5 . A preparation method for the negative electrode material according to claim 1 , comprising following steps:

mixing a first graphite and a second graphite and performing a coating treatment to obtain the first graphite coated by the second graphite, wherein the second graphite is of graphite microcrystal; and

making the first graphite coated by the second graphite, coated with carbon, to obtain the negative electrode material.

6 . The preparation method according to claim 5 , wherein the preparation method satisfies at least one of following conditions a-j:

a. the graphite microcrystal is at least partially embedded in the first graphite;

b. the first graphite is spheroidal natural graphite;

c. the first graphite has a median particle diameter of 2.0 μm-30.0 μm;

d. the first graphite is spheroidal natural graphite, and a mass percentage content of fixed carbon in the natural graphite is ≥99.9%;

e. a ratio of the median particle diameter of the first graphite to a median particle diameter of the graphite microcrystal is 5:1-50:1;

f. the median particle diameter of the graphite microcrystal is 0 μm-2 μm, not including 0 μm;

g. the negative electrode material has a median particle diameter of 2 μm-32 μm, not including 2 μm;

h. the negative electrode material has a specific surface area of 0.5 m 2 /g-20.0 m 2 /g;

i. the negative electrode material has a powder-body tap density of 0.5 g/cm 3 -1.3 g/cm 3 ; and

j. the composite coating layer has a thickness of 0 μm-5 μm, not including 0 μm.

7 . The preparation method according to claim 5 , wherein, before mixing and coating the first graphite and the second graphite, the method further comprises:

purifying the graphite microcrystal with an acidic aqueous solution, so that the fixed carbon content of the graphite microcrystal is ≥99.9%.

8 . The preparation method according to claim 7 , wherein steps of purifying the graphite microcrystal comprises:

crushing the graphite microcrystal, so that a median particle diameter of particles of the graphite microcrystal is controlled within 0 μm-2 μm, not including 0 μm; and

purifying the graphite microcrystal with the acidic aqueous solution, so that the fixed carbon content of the graphite microcrystal is ≥99.9%.

9 . The preparation method according to claim 7 , wherein the preparation method satisfies at least one of following conditions a-b:

a. acid in the acidic aqueous solution is inorganic acid; and

b. acid in the acidic aqueous solution is inorganic acid, and the inorganic acid comprises at least one of HCl, HF, H 2 SO 4 and HNO 3 .

10 . The preparation method according to claim 5 , wherein the preparation method satisfies at least one of following conditions a-e:

a. a mass ratio of the first graphite to the second graphite is (80-100):(0-20), and a mass of the second graphite is not 0;

b. the mass ratio of the first graphite to the second graphite is (90-100):(1-10);

c. using a fusion machine for performing a coating treatment, wherein a rotation speed of the fusion machine is 500 r/min-3000 r/min;

d. using a fusion machine for performing a coating treatment, wherein a cutter gap of the fusion machine has a width of 0.01 cm-0.5 cm; and

e. a duration of the coating treatment is 10 min-120 min.

11 . The preparation method according to claim 5 , wherein a step of making the first graphite coated by the second graphite, coated with carbon, to obtain the negative electrode material comprises:

making, the first graphite coated by the second graphite, mixed with an amorphous carbon precursor, and performing a carbonization treatment in a protective atmosphere, to obtain the negative electrode material.

12 . The preparation method according to claim 11 , wherein the preparation method satisfies at least one of following conditions a-j:

a. a mass ratio of the first graphite coated by the second graphite and the amorphous carbon precursor is (80-100):(0-20), and a mass of the amorphous carbon precursor is not 0;

b. the mass ratio of the first graphite coated by the second graphite and the amorphous carbon precursor is (80-100):(2-20);

c. the amorphous carbon precursor comprises asphalt and/or resin;

d. the amorphous carbon precursor comprises asphalt, and the asphalt comprises at least one of coal asphalt, petroleum asphalt, modified asphalt, and mesophase asphalt;

e. the amorphous carbon precursor comprises resin, and the resin comprises at least one of phenolic resin, epoxy resin and furfural resin;

f. the mixing has a duration more than 5 min;

g. gas of the protective atmosphere comprises at least one of nitrogen, helium, neon, argon and xenon;

h. a temperature of the carbonization treatment is 800° C.-1400° C.;

i. a duration of the carbonization treatment is 1 h-72 h; and

j. a heating rate of the carbonization treatment is below 20.0° C./min.

13 . The preparation method according to claim 5 , wherein after the first graphite coated by the second graphite is coated with carbon to obtain the negative electrode material, the method further comprises:

making the negative electrode material crushed, sieved and demagnetized, so that a median particle diameter of the negative electrode material is controlled at 2.0 μm-30.0 μm.

14 . The preparation method according to claim 5 , wherein the method comprises following steps:

purifying the graphite microcrystal with the acidic aqueous solution, so that the fixed carbon content is greater than or equal to 99.9%;

mixing natural graphite and graphite microcrystal powder based on a mass ratio of (90-100):(1-10), and carrying out the coating treatment for 10 min-120 min, so as to obtain the natural graphite coated by the graphite microcrystal; and

mixing the natural graphite coated by the graphite microcrystal and an amorphous carbon precursor based on a mass ratio of (80-100):(2-20); and increasing a temperature to 800° C. to 1400° C. at a heating rate of 1.0° C./min-5.0° C./min and performing a carbonization treatment for 1 h to 24 h, under a protective gas atmosphere, to obtain the negative electrode material.

15 . A lithium ion battery, wherein the lithium ion battery comprises the negative electrode material according to claim 1 .

16 . The negative electrode material according to claim 2 , wherein the graphite microcrystal satisfies at least one of following conditions a to d:

a. the graphite microcrystal is at least partially embedded in the first graphite core;

b. the median particle diameter of the graphite microcrystal is 0 μm-2 μm, not including 0 μm;

c. a fixed carbon content of the graphite microcrystal is ≥99.9%; and

d. a powder-body tap density of the graphite microcrystal is 0 g/cm 3 -0.5 g/cm 3 , not including 0 g/cm 3 .

17 . The negative electrode material according to claim 2 , wherein the negative electrode material satisfies at least one of following conditions a-e:

a. a median particle diameter of the negative electrode material is 2 μm-32 μm, not including 2 μm;

b. the negative electrode material has a specific surface area of 0.5 m 2 /g-20.0 m 2 /g;

c. a powder-body tap density of the negative electrode material is 0.5 g/cm 3 -1.3 g/cm 3 ;

d. the composite coating layer has a thickness of 0 μm-5 μm, not including 0 μm; and

e. the amorphous carbon outer layer has a thickness of 0 nm-500 nm, not including 0 nm.

18 . The preparation method according to claim 8 , wherein the preparation method satisfies at least one of following conditions a-b:

a. acid in the acidic aqueous solution is inorganic acid; and

b. acid in the acidic aqueous solution is inorganic acid, and the inorganic acid comprises at least one of HCl, HF, H 2 SO 4 and HNO 3 .

19 . The preparation method according to claim 6 , wherein the preparation method satisfies at least one of following conditions a-e:

a. a mass ratio of the first graphite to the second graphite is (80-100):(0-20), and a mass of the second graphite is not 0;

b. the mass ratio of the first graphite to the second graphite is (90-100):(1-10);

c. using a fusion machine for performing a coating treatment, wherein a rotation speed of the fusion machine is 500 r/min-3000 r/min;

d. using a fusion machine for performing a coating treatment, wherein a cutter gap of the fusion machine has a width of 0.01 cm-0.5 cm; and

e. a duration of the coating treatment is 10 min-120 min.

20 . The preparation method according to claim 6 , wherein a step of making the first graphite coated by the second graphite, coated with carbon, to obtain the negative electrode material comprises:

making, the first graphite coated by the second graphite, mixed with an amorphous carbon precursor, and performing a carbonization treatment in a protective atmosphere, to obtain the negative electrode material.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (21)