Composite artificial graphite and preparation method thereof, and secondary battery and power consuming device comprising the composite artificial graphite
View Patent ↗A composite artificial graphite includes a first graphite and a second graphite. The first graphite includes secondary particles and has a graphite interlayer spacing d 002 of 0.33560 nm to 0.33610 nm. The second graphite includes primary particles and has a graphite interlayer spacing d 002 of 0.33620 nm to 0.33670 nm. A mass percentage of the first graphite in the composite artificial graphite is 40% to 90%.
1. A preparation method of a composite artificial graphite, comprising:
preparing a first graphite, comprising:
crushing, grading, and shaping a first raw material to obtain a first precursor;
granulating the first precursor to obtain a first intermediate; and
graphitizing the first intermediate at a temperature of 2800° C. to 3200° C. to obtain the first graphite;
wherein the first graphite includes secondary particles and has a graphite interlayer spacing of 0.33560 nm to 0.33610 nm;
preparing a second graphite, comprising:
crushing, grading, and shaping a second raw material to obtain a second precursor;
graphitizing the second precursor at a temperature of 2500° C. to 2700° C. to obtain the second graphite;
wherein the second graphite includes primary particles and has a graphite interlayer spacing of 0.33620 nm to 0.33670 nm; and
uniformly mixing the first graphite and the second graphite at a mass percentage of the first graphite of 40% to 90% and a mass percentage of the second graphite of 10% to 60%, to obtain the composite artificial graphite, wherein the mass percentage of the first graphite and the mass percentage of the second graphite are based on a weight of the composite artificial graphite.
2. The preparation method according to claim 1 , wherein a binder is added during granulating the first precursor, and an amount of the binder is 4% to 16% of a weight of the first precursor.
3. The preparation method according to claim 1 , wherein:
the first raw material comprises one or more of a needle green petroleum coke, a non-needle green petroleum coke, a needle green coke of coal measures, a non-needle green coke of coal measures, a calcined needle coke, and a calcined petroleum coke; and
the second raw material comprises one or more of a needle green petroleum coke, a non-needle green petroleum coke, a needle green coke of coal measures, a non-needle green coke of coal measures, a calcined needle coke, and a calcined petroleum coke.
4. The preparation method according to claim 1 , wherein the first intermediate is graphitized at a temperature of 3000° C. to 3200° C., and the second precursor is graphitized at a temperature of 2500° C. to 2600° C.
5. The composite artificial graphite prepared by the preparation method of claim 1 , comprising the first graphite and the second graphite.
6. The composite artificial graphite according to claim 5 , wherein a volume mean particle size D v 50 of the composite artificial graphite is 11.5 μm to 21.5 μm.
7. The composite artificial graphite according to claim 5 , wherein a number particle size distribution D n 10 of the composite artificial graphite is 1.3 μm to 6.5 μm.
8. The composite artificial graphite according to claim 5 , wherein a powder compacted density of the composite artificial graphite under a pressure of 2000 kg is 1.55 g/cm 3 to 1.85 g/cm 3 .
9. The composite artificial graphite according to claim 5 , wherein a gram capacity of the composite artificial graphite is 335 mAh/g or more.
10. The composite artificial graphite according to claim 5 , wherein:
a volume mean particle size D v 50 of the first graphite is 11.5 μm to 21.5 μm;
a number particle size distribution D n 10 of the first graphite is 1.5 μm to 7.5 μm;
a volume mean particle size D v 50 of the second graphite is 8.0 μm to 20.0 μm; and/or
a number particle size distribution D n 10 of the second graphite is 1.2 μm to 6.0 μm.
11. The composite artificial graphite according to claim 5 , wherein:
a degree of graphitization of the first graphite is 91% to 97%; and or
a degree of graphitization of the second graphite is 85% to 90%.
12. A secondary battery, comprising a negative electrode plate comprising a negative electrode active material, the negative electrode active material comprising the composite artificial graphite prepared by the preparation method of claim 1 , comprising the first graphite and the second graphite.
13. A battery module, comprising the secondary battery according to claim 12 .
14. A battery pack, comprising the battery module according to claim 13 .
15. A power consuming device, comprising the secondary battery according to claim 12 .