Core-shell-type cathode active material for lithium secondary battery, method of manufacturing same, and lithium secondary battery including same

1 . A core-shell structured cathode active material for a lithium secondary battery comprising a core satisfying Formula 2 below and a shell satisfying Formula 3 below, wherein the cathode active material of the core-shell structure is doped with a Group 13 element:

LiNi x Co 1-x O 2 where, x is a real number satisfying 0.9 ≤x ≤1.0;  [Formula 2]

LiNi x Co 1-x O 2 where, x is a real number satisfying 0.8 ≤x ≤0.9,  [Formula 3]

wherein the shell has a thickness in a range of 300 nm to 1000 nm, and

at a position having a depth of 100 nm from an outer surface of the shell, nickel in the shell comprises Ni 3+ in an amount of 85% or greater based on a total amount of nickel present at the depth.

2 . The cathode active material of claim 1 , wherein the cathode active material has a nickel content in a range of 15% to 25% by mole.

3 . The cathode active material of claim 1 , wherein the core-shell shell has a trigonal crystal structure.

4 . The cathode active material of claim 1 , wherein the Group 13 element is any one or more elements selected from among B, Al, Ga, and In.

5 . The cathode active material of claim 4 , wherein the cathode active material is doped with B and Al among the Group 13 elements.

6 . The cathode active material of claim 5 , wherein the cathode active material is doped with B in a B:Li molar ratio of 1:0.005 to 0.015.

7 . The cathode active material of claim 5 , wherein the cathode active material is doped with Al in an Al:Li molar ratio of 1:0.010 to 0.020.

8 . A lithium secondary battery cathode comprising the cathode active material of claim 1 .