Lithium-rich antiperovskite-coated LCO-based lithium composite, method for preparing same, and positive electrode active material and lithium secondary battery comprising same

1. An LCO-based lithium complex comprising a coating layer and a core, wherein the coating layer comprises a lithium-rich antiperovskite (LiRAP) compound, wherein the core comprises LCO-based particles; wherein the coating layer is applied onto the core; and

wherein the LCO-based particles comprise one or more of the following chemical compounds:

(1) LiCoO 2

(2) Li 1-a CoO 2 (0<a<1)

(4) LiMn 1-d O 2 (0≤d<1)

(5) LiMn 2-e Co e O 4 (0<e<2)

(6) LiNi 1-f Co f O 2 (0≤f<1)

(7) LiNi 1-g-h CoM h O 2 (M=Al, Sr, Mg, or La, 0≤g≤1, 0≤h≤1, and 0≤g+h≤1)

(8) Li(Ni j Co k Mn l )O 2 (0<j<1, 0<k<1, 0<1<1, and j+k+l=1)

(9) Li(Ni m Co n Mn o )O 4 (0<m<2, 0<n<2, 0<o<2, and m+n+o=2)

(W) Li 1+p Ni q Co r Me s O 2 (Me=SC, Y, La, Rh, Ir, Al, Ga, In, or Ta, 0.02≤p≤0.2, 0.4≤q≤0.58, 0.4≤r≤0.5, 0.0≤s≤0.1, and p+q+r+s=1)

(11) Li t Ni u Mn v Co w O 2 (1≤t≤1.2, u=1−v−w, 0<v<1, 0<w<1, u>v, w=nv, or v=nw, and n>1).

2. The LCO-based lithium complex of claim 1 , wherein the LCO-based particles have an average particle diameter of 1 to 1,000 nm.

3. The LCO-based lithium complex of claim 1 , wherein the LCO-based particles has a surface continuously or discontinuously coated with one or more lithium-reactive elements selected from the group consisting of Ti, W, Zr, Mn, Mg, P, Ni, Al, Sn, V, Cr, and Mo.

4. The LCO-based lithium complex of claim 1 , wherein the lithium-rich antiperovskite compound comprises one or more selected from the following chemical compounds:

(12) Li 3 OCl

(13) Li (3-a) M a/2 OHal (M=Mn, Ca, Ba, or Sr, Hal=F, Cl, Br, or I, and 0<a<3)

(14) Li (3-b) N (b/3 )OHal (N=a trivalent metal, Hal=F, Cl, Br, or I, and 0≤b≤3)

(15) LiOX c Y (1-c) , (X and Y are different halides, and 0≤c≤1)

(16) Li 3-d ClO 1-d Hal d (Hal=F, Cl, Br, or I, and 0<d<1)

(17) Li 3-e-f A e O 1-f Hal f Cl (A=Na, or K, Hal=F, Cl, Br, or I, 0<e<2, and 0<f<1)

(18) Li 3-2-g-h M g O 1-h Hal h Cl (M=Mg, Mn, Ca, Ba, or Sr, Hal=F, Cl, Br, or I, 0<g<1, and 0<h<1).

5. The LCO-based lithium complex of claim 1 , wherein the lithium-rich antiperovskite compound has an ion conductivity of 10 to 10 −10 S/cm.

6. The LCO-based lithium complex of claim 1 , wherein the coating layer has a content of the lithium-rich antiperovskite compound that is less than or equal to 20% by weight, based on a total of 100% by weight of the complex.

7. The LCO-based lithium complex of claim 1 , wherein the coating layer has a thickness of 1 nm to 100 μm.

8. A method of preparing the LCO-based lithium complex defined in claim 1 , comprising:

preparing a mixed solution of a lithium-rich antiperovskite compound precursor;

mixing the mixed solution with LCO-based particles; and

forming a coating layer of a lithium-rich antiperovskite compound on the LCO-based particles by means of a sol-gel process and heat treatment.

9. A positive electrode active material for lithium secondary batteries comprising the LCO-based lithium complex defined in claim 1 .

10. A lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte interposed between the positive and negative electrodes,

wherein the positive electrode comprises the positive electrode active material defined in claim 9 .