METHOD FOR PRODUCING NEGATIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME
Presented is a method for producing a negative electrode active material which has a high discharge capacity, high charge-discharge efficiency, and excellent high-output characteristics, and which experiences only a small volume change during charging/discharging. A method for producing a negative electrode active material for a lithium secondary battery according to an embodiment of the present invention includes: a step for producing primary particles by pulverizing a carbon raw material containing 4 to 10 wt % of volatile matters; a step for producing secondary particles by mixing the primary particles with a binder; and a step for producing a graphite material by graphitizing the secondary particles.
1 . A method for producing a negative electrode active material for a lithium secondary battery, comprising:
a step for producing primary particles by pulverizing a carbon raw material containing 4 to 10 wt % of volatile components;
a step for producing secondary particles by mixing the primary particles with a binder; and
a step for producing a graphite material by graphitizing the secondary particles.
2 . The method of claim 1 , wherein
the carbon raw material includes a green coke or a raw coke.
3 . The method of claim 1 , wherein
a particle diameter of D 50 of the primary particles is equal to or less than 10 μm.
4 . The method of claim 1 , wherein
sphericity of the primary particles is 0.75 to 1.
5 . The method of claim 1 , further comprising
a step for grinding the primary particles after the step for producing primary particles.
6 . The method of claim 1 , further comprising
a step for raising a temperature of the primary particles at a rate of 1 to 10° C./min after the step of producing primary particles.
7 . The method of claim 1 , further comprising
a step for removing a volatile matter in the primary particles by heat-treating the primary particles after the step for producing primary particles.
8 . The method of claim 7 , wherein
a heat treatment temperature is 800 to 1500° C. in the step for removing a volatile matter in the primary particles.
9 . The method of claim 1 , wherein
the binder at 2 to 20 parts by weight is mixed with the primary particles at 100 parts by weight in the step for producing secondary particles.
10 . The method of claim 1 , wherein
the binder includes a coal pitch or a petroleum pitch.
11 . The method of claim 1 , wherein
the binder has a softening point of 80 to 300° C.
12 . The method of claim 1 , wherein
the step for producing secondary particles is performed for one to five hours at a temperature of 110 to 500° C.
13 . The method of claim 1 , wherein
a particle diameter D 50 of the secondary particles is 14 to 25 μm.
14 . The method of claim 1 , further comprising
a step for carbonizing the secondary particles after the step for producing secondary particles.
15 . The method of claim 14 , wherein
the carbonization step is performed at a temperature of 800 to 1500° C.
16 . The method of claim 1 , wherein
the step for producing a graphite material is performed at a temperature of 2800 to 3200° C.
17 . The method of claim 1 , wherein
the graphite material has a BET that is equal to or less than 1.7 m 2 /g and tab density that is equal to or greater than 0.7 g/cc.
18 . A lithium secondary battery comprising:
a positive electrode; a negative electrode; and an electrolyte,
wherein the negative electrode includes a negative electrode active material for a lithium secondary battery produced by a method according to claim 1 .