	US 12,218,354 B2
	Negative-electrode active material and preparation method thereof, secondary battery, and battery module, battery pack, and apparatus containing such secondary battery
Yuqun Zeng, Ningde (CN); Baida Deng, Ningde (CN); Meng Kang, Ningde (CN); Erling Li, Ningde (CN); and Libing He, Ningde (CN)
Assigned to CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed by CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed on Aug. 25, 2022, as Appl. No. 17/822,260.
Application 17/822,260 is a continuation of application No. PCT/CN2020/121268, filed on Oct. 15, 2020.
Prior Publication US 2022/0416244 A1, Dec. 29, 2022
Int. Cl. H01M 4/04 (2006.01); H01M 4/02 (2006.01); H01M 4/583 (2010.01); H01M 4/62 (2006.01)

CPC H01M 4/583 (2013.01) [H01M 4/0471 (2013.01); H01M 4/622 (2013.01); H01M 4/625 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)]

6 Claims

1. A preparation method for a negative-electrode active material, comprising:

preparing a core material, wherein the core material comprises granulated artificial graphite;

mixing the core material with an organic carbon source; and

heat treating the mixed core material at 700-1800° C., to form the negative-electrode active material having an amorphous carbon coating layer covering at least part of surfaces of the core material, wherein a graphitization degree of the negative-electrode active material is 91.0%-96.0%;

wherein the granulated artificial graphite is prepared by a process that comprises:

pulverizing a coke raw material;

shaping the pulverized coke raw material to obtain a precursor;

granulating the precursor to obtain a granulated product, wherein the granulated product comprises primary particles and secondary particles, and the secondary particles are obtained by agglomerating independently dispersed primary particles; and

graphitizing the granulated product at a temperature of 2800° C. to 3200° C., to obtain the granulated artificial graphite,

wherein, after pulverization, a volume-based median particle size D_v50 of the coke raw material is 7 μm-12 μm, and a volume-based particle size distribution D_v99 of the coke raw material is 15 μm-21 μm;

wherein, after the shaping, a volume-based median particle size D_v50 of the precursor is 8 μm-13 μm, a volume-based particle size distribution D_v99 of the precursor is 16 μm-22 μm, and a particle size uniformity of the precursor U₁satisfies 0.2≤U₁≤0.55;

wherein a volume-based median particle size D_v50 of the granulated product is 9 μm-15 μm, and a volume-based particle size distribution D_v99 of the granulated product is 17 μm-24 μm;

wherein a volume-based median particle size D_v50 of the granulated artificial graphite is 6 μm-14 μm, a volume-based particle size distribution D_v99 of the granulated artificial graphite is 17 μm-26 μm, and a particle size uniformity of the granulated artificial graphite U₂satisfies 0.22≤U₂≤0.48; and

wherein a particle size specific surface area of the negative-electrode active material is 0.4 m²/g-0.75 m²/g.