ARTIFICIAL GRAPHITE, PREPARATION METHOD THEREFOR AND USE THEREOF
The present application discloses an artificial graphite, a preparation method therefor and the use thereof. A method for preparing an artificial graphite of an embodiment of the present application comprises the following step: subjecting a graphite raw material to a heat treatment to obtain the artificial graphite, wherein an environmental atmosphere for the heat treatment is at least one gas of air and carbon dioxide or a mixed gas of at least one gas of air and carbon dioxide and a chemically inert gas; and during the heat treatment, the graphite raw material is in a static state. The method realizes at least modifying a surface of the graphite raw material by controlling the heat treatment conditions for the graphite raw material, such that the prepared artificial graphite has an appropriately low compaction rebound capacity, a high and stable compacted density, and a good cycling performance.
1 . A method for preparing an artificial graphite, characterized by comprising the following step:
subjecting a graphite raw material to a heat treatment to obtain the artificial graphite,
wherein an environmental atmosphere for the heat treatment is at least one gas of air and carbon dioxide or a mixed gas of at least one gas of air and carbon dioxide and a chemically inert gas; and during the heat treatment, the graphite raw material is in a static state.
2 . The preparation method according to claim 1 , characterized in that a temperature for the heat treatment is 500-900° C.; or
the temperature for the heat treatment is 500-900° C. and a time for the heat treatment is 30-180 min.
3 . The preparation method according to claim 1 , characterized in that in the mixed gas, the at least one gas of air and carbon dioxide accounts for 5%-40% of a total volume of the mixed gas;
a particle size Dv50 of the graphite raw material is 6-15 μm; and/or
the graphite raw material is an artificial graphite raw material.
4 . The preparation method according to claim 3 , characterized in that a method for preparing the artificial graphite raw material comprises the following steps:
crushing a solid carbon source to obtain a granular solid carbon source;
shaping the granular solid carbon source to obtain a shaped particle; and
graphitizing the shaped particle to obtain the artificial graphite raw material.
5 . The preparation method according to claim 4 , characterized in that the particle size Dv50 of the granular solid carbon source is 5-15 μm; and/or
the solid carbon source comprises at least one of a petroleum coke, a needle coke, a pitch coke, and a metallurgical coke;
the graphitization is carried out at a temperature of 2,800-3,200° C.; and/or
the method further comprises a step of granulating the shaped particle before the graphitizing the shaped particle.
6 . The preparation method according to claim 5 , characterized in that the granulating comprises the following step:
mixing a carbon source binder and the shaped particle, followed by granulating and shaping.
7 . An artificial graphite, characterized in that the artificial graphite is an artificial graphite prepared by a preparation method according to claim 1 .
8 . The artificial graphite according to claim 7 , characterized in that a compacted density and a rebound rate of the artificial graphite satisfy the following relationship:
0.08 cm 3 /g≤η/ P 5k ≤0.15 cm 3 /g, and η=( L pressure releasing −L pressure maintaining )/ L pressure maintaining ,
wherein the P 5k is a compacted density of a powder of the artificial graphite under a pressure of 5,000 kg, in g/cm 3 ; the L pressure maintaining is a thickness of the powder of the artificial graphite when being maintained at the pressure of 5,000 kg; and the L pressure releasing is the thickness of the powder of the artificial graphite after the pressure is released after the pressure of 5,000 kg is applied.
9 . The artificial graphite according to claim 7 , characterized in that the η/P 5k is 0.10 cm 3 /g≤η/P 5k ≤0.13 cm 3 /g.
10 . The artificial graphite according to claim 7 , characterized in that the P 5k is 1.83-2.08 g/cm 3 ; and/or
the η is 15.0%-32%.
11 . The artificial graphite according to claim 7 , characterized in that the P 5k is 1.85-2.05 g/cm 3 .
12 . The artificial graphite according to claim 7 , characterized in that the artificial graphite further has at least one of the following properties:
a particle size Dv50 of the artificial graphite is 6-15 μm; and/or
the BET specific surface area of the artificial graphite is 1.7-2.5 m 2 /g; and/or
the OI value of the artificial graphite is 5-15; and/or
the resistivity of the powder of the artificial graphite under a pressure of 8 Mpa is 0.008 Ω·cm-0.055 Ω·cm; and/or
the tap density of the artificial graphite is 0.80-1.19 g/cm 3 ; and/or
the degree of graphitization G of the artificial graphite is 91%-95%; and/or
the capacity per gram of the artificial graphite is 343-365 mAh/g.
13 . The artificial graphite according to claim 7 , characterized in that the artificial graphite further has at least one of the following properties:
the specific surface area of the artificial graphite is 1.7-2.2 m 2 /g; and/or
the OI value of the artificial graphite is 5-10; and/or
the resistivity of the powder of the artificial graphite under the pressure of 8 Mpa is 0.01 Ω·cm-0.042 Ω·cm; and/or
the tap density of the artificial graphite is 0.85-1.16 g/cm 3 ; and/or
the capacity per gram of the artificial graphite is 345-360 mAh/g.
14 . A negative electrode material, characterized by comprising an artificial graphite, wherein the artificial graphite is an artificial graphite according to claim 7 .
15 . A negative electrode, characterized in that a negative electrode material contained in the negative electrode comprises an artificial graphite according to claim 7 or a negative electrode material according to claim 14 .
16 . A battery, characterized by comprising a negative electrode according to claim 15 .
17 . A power consuming device, characterized in that the power consuming device comprises a battery according to claim 16 , and the battery is configured to supply electric energy.