Artificial graphite, preparation method thereof, secondary battery containing the same and power consuming device
An artificial graphite satisfies: PD 5t /PD 0.5t ≤1.35, where PD 5t is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD 0.5t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton.
1. An artificial graphite, satisfying: PD 5t /PD 0.5t ≤1.35, and PD 0.5t ≥1.4 g/cm 3 , wherein PD 5t /PD 0.5t characterizes a sensitivity of the artificial graphite to pressure changes, PD 5t is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD 0.5t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton; a median particle size Dv50 of the artificial graphite satisfies: Dv50≥10 μm; a specific surface area SSA of the artificial graphite satisfies: SSA≤1.5 g/m 2 ; and a tap density of the artificial graphite is 0.9 g/cm 3 or more.
2. The artificial graphite according to claim 1 , wherein the artificial graphite satisfies: 1.23≤PD 5t /PD 0.5t ≤1.3.
3. The artificial graphite according to claim 1 , wherein the artificial graphite satisfies: PD 5t ≥1.8 g/cm 3 .
4. The artificial graphite according to claim 1 , wherein a degree of graphitization of the artificial graphite is 90% or more.
5. The artificial graphite according to claim 1 , wherein a gram capacity of the artificial graphite is 340 mAh/g or more.
6. A secondary battery comprising an artificial graphite that satisfies: PD 5t /PD 0.5t ≤1.35, and PD 0.5t ≥1.4 g/cm 3 , wherein PD 5t /PD 0.5t characterizes a sensitivity of the artificial graphite to pressure changes, PD 5t is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD 0.5t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton; a median particle size Dv50 of the artificial graphite satisfies: Dv50≥10 μm; a specific surface area SSA of the artificial graphite satisfies: SSA≤1.5 g/m 2 ; and a tap density of the artificial graphite is 0.9 g/cm 3 or more.
7. A method for preparing an artificial graphite, comprising:
preparing green coke particles, calcined coke particles, a binder, and a solvent into a mixture;
forming the mixture to obtain an intermediate;
removing at least part of the solvent from the intermediate to obtain a green compact;
graphitizing the green compact to obtain a graphite compact; and
making the graphite compact into a powder to obtain the artificial graphite;
wherein the artificial graphite satisfies: PD 5t /PD 0.5t ≤1.35, and PD 0.5t ≥1.4 g/cm 3 , wherein PD 5t /PD 0.5t characterizes a sensitivity of the artificial graphite to pressure changes, PD 5t is a compacted density of the artificial graphite measured under a pressure of 5 ton, and PD 0.5t is a compacted density of the artificial graphite measured under a pressure of 0.5 ton; a median particle size Dv50 of the artificial graphite satisfies: Dv50≥10 μm; a specific surface area SSA of the artificial graphite satisfies: SSA≤1.5 g/m 2 ; and a tap density of the artificial graphite is 0.9 g/cm 3 or more.
8. The method according to claim 7 , wherein a content of the green coke particles is 35 wt % or more of a total mass of the green coke particles, the calcined coke particles, and the binder.
9. The method according to claim 7 , wherein a content of the binder is 2 wt % or more of a total mass of the green coke particles, the calcined coke particles, and the binder.
10. The method according to claim 7 , wherein a volatile content of the green coke particles is ≥6 wt %.
11. The method according to claim 7 , wherein an apparent density of the green compact is 1.3 g/cm 3 or more.
12. The method according to claim 7 , wherein a packing density of the green compact is 0.85 g/cm 3 or less.
13. The method according to claim 7 , wherein the green compact has one or more features of following:
a dimension of the green compact in at least one direction is ≥1 cm;
dimensions of the green compact in at least two directions perpendicular to each other are both ≥1 cm;
dimensions of the green compact in three directions perpendicular to each other are all ≥1 cm; and
a shape of the green compact is selected from one or more of a columnar shape, a spherical shape, an ellipsoidal shape, and a bulky shape.
14. The method according to claim 7 , wherein one or more of following features are satisfied:
a median particle size Dv50 of the green coke particles is less than a median particle size Dv50 of the calcined coke particles;
the median particle size Dv50 of the green coke particles is 15 μm or less; and
the median particle size Dv50 of the calcined coke particles is 20 μm or less.
15. The method according to claim 7 , wherein the binder is evaporable or decomposable at 1000° C. or more.
16. The method according to claim 7 , wherein the binder is a polymeric binder.