Cathode active material for lithium secondary battery, method for manufacturing same, and lithium secondary battery comprising same
The present invention relates to a positive active material for lithium secondary battery, its manufacturing method, and lithium secondary battery including the same, and it provides that a positive active material for lithium secondary battery, comprising: a core and a coating layer, wherein, the core is lithium metal oxide, the coating layer comprises boron, the boron compound in the coating layer comprises a lithium boron oxide and a boron oxide, the lithium boron oxide is included 70 wt % or more and 99 wt % in the entire coating layer, the lithium boron oxide comprises Li 2 B 4 O 7 , with respect to the lithium boron oxide 100 wt %, the content of Li 2 B 4 O 7 is 55 wt % or more and 99 wt % or less.
1. A positive active material for lithium secondary battery, comprising:
a core and a coating layer,
wherein, the core is lithium metal oxide,
the coating layer comprises boron,
a boron compound in the coating layer comprises a lithium boron oxide and a boron oxide,
the lithium boron oxide is included 70 wt % or more and 99 wt % in the entire coating layer,
the lithium boron oxide comprises Li 2 B 4 O 7 ,
with respect to the lithium boron oxide 100 wt %, the content of Li 2 B 4 O 7 is 55 wt % or more and 99 wt % or less.
2. The positive active material of claim 1 , wherein:
the lithium boron oxide further comprises Li 3 BO 3 .
3. The positive active material of claim 1 , wherein:
with respect to the lithium boron oxide 100 wt %, the content of B 2 O 3 is 20 wt % or less.
4. The positive active material of claim 1 , wherein:
with respect to the lithium boron oxide 100 wt %, the content of Li 3 BO 3 is 1 wt % or less.
5. A lithium secondary battery, comprising:
a positive electrode containing positive active material according to claim 1 ;
a negative electrode, and
an electrolyte positioned between the positive and negative electrode.
6. A method of manufacturing a positive active material for lithium secondary battery, comprising:
preparing a metal hydroxide precursor;
obtaining a lithium metal oxide by mixing and sintering the metal hydroxide precursor and a lithium raw material;
washing the lithium metal oxide; and
obtaining a positive active material by mixing and heat treating the washed lithium metal oxide and a coating material;
wherein, the coating material comprises boron,
the obtained positive active material comprises a core and a coating layer, wherein the core is lithium metal oxide,
a boron compound in the coating layer comprises a lithium boron oxide and a boron oxide,
the lithium boron oxide is included 70 wt % or more and 99 wt % in the entire coating layer,
the lithium boron oxide comprises Li 2 B 4 O 7 , and
with respect to the lithium boron oxide 100 wt %, the content of Li 2 B 4 O 7 is 55 wt % or more and 99 wt % or less.
7. The method of claim 6 , wherein:
in the step of obtaining a positive active material by mixing and heat treating the washed lithium metal oxide and a coating material;
a residual lithium of the washed lithium metal oxide is 2,000 to 3,000 ppm, and
a sintering temperature is above 350° C. and below 450° C.
8. The method of claim 7 , wherein:
in the step of obtaining a lithium metal oxide by mixing and sintering the metal hydroxide precursor and a lithium raw material;
the lithium raw material is LiOH.
9. The method of claim 6 , wherein:
in the step of obtaining a positive active material by mixing and heat treating the washed lithium metal oxide and a coating material;
a residual lithium of the washed lithium metal oxide is 1,000 to 2,000 ppm, and
a sintering temperature is above 250° C. and below 350° C.
10. The method of claim 9 , wherein:
in the step of obtaining a lithium metal oxide by mixing and sintering the metal hydroxide precursor and a lithium raw material;
the lithium raw material is Li 2 CO 3 .