Anode active material for lithium secondary battery and method of manufacturing same
The present disclosure relates to a method of manufacturing an anode active material for a lithium secondary battery, the method including: mixing earth graphite and pitch coke with each other; preparing a raw material by adding and mixing a binder to the mixture; performing heat treatment on the raw material; graphitizing the heat-treated mixture to obtain a core part; immersing the core part in a hard carbon coating solution; and drying the coating solution in which the core part is immersed to obtain an anode active material.
1 . An anode active material for a lithium secondary battery, comprising:
a core part in which earth graphite and coal-based calcined pitch coke are mixed with each other; and
a hard carbon coating for coating the core part,
wherein a mixing ratio of the earth graphite to the coal-based calcined pitch coke is 30:70 to 70:30.
2 . The anode active material for a lithium secondary battery of claim 1 , wherein:
a thickness of the hard carbon coating part is 10 to 700 nm.
3 . The anode active material for a lithium secondary battery of claim 1 , wherein:
a degree of graphitization of the earth graphite is 90% or more.
4 . The anode active material for a lithium secondary battery of claim 1 , wherein:
the anode active material for a lithium secondary battery exhibits a volume expansion rate of less than 20% after 50 cycles at a 5C-rate.
5 . The anode active material for a lithium secondary battery of claim 1 , wherein:
the earth graphite has a crystallite size La of 20 to 50 nm and a crystallite size Lc of 10 to 40 nm, when measured by X-ray diffraction (XRD).
6 . The anode active material for a lithium secondary battery of claim 1 , wherein:
an average particle size D50 of the anode active material for a lithium secondary battery is 14 to 19 μm.
7 . The anode active material for a lithium secondary battery of claim 1 , wherein:
the anode active material for a lithium secondary battery has a specific surface area (BET) of 0.9 to 1.3 m 2 /g.
8 . The anode active material for a lithium secondary battery of claim 1 , wherein:
the hard carbon results from carbonization of a source that is one or more selected from the group consisting of a phenolic resin, a naphthalene resin, a furfuryl alcohol resin, a polyamide resin, a furan resin, a polyimide resin, an epoxy resin, a vinyl chloride resin, gum arabic, citric acid, stearic acid, sucrose, polyvinylidene fluoride, carboxymethyl cellulose (CMC), hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, an ethylene propylene diene monomer (EPDM), a sulfonated EPDM, starch, polyacrylic acid, sodium polyacrylate, polyacrylonitrile, cellulose, styrene, polyvinyl alcohol, and polyvinyl chloride.