Lithium transition metal composite particles, preparation method thereof, and cathode active material including the same

1. A lithium transition metal composite particle comprising:

a lithium transition metal oxide particle;

a zirconium-doped layer formed by doping the lithium transition metal oxide particle;

LiF formed on the lithium transition metal oxide particle including the zirconium-doped layer,

wherein the zirconium-doped layer comprises composite particles of Chemical Formula 1:

Li a M 1-b Zr b O 2   <Chemical Formula 1>

where M=Ni x Mn y Co z , (0.3≦x≦0.9, 0≦y≦0.6, and 0≦z≦0.6),

0.9≦a≦1.3, and

0≦b≦0.02.

2. The lithium transition metal composite particle of claim 1 , wherein the zirconium-doped layer is included in an amount of 0.01 wt % to 3 wt % based on 100 wt % of the lithium transition metal composite particle.

3. The lithium transition metal composite particle of claim 1 , wherein the zirconium has a concentration gradient in which a concentration gradually decreases from a surface of the lithium transition metal oxide particle to inside thereof.

4. The lithium transition metal composite particle of claim 1 , wherein the zirconium-doped layer further comprises an oxide including the zirconium.

5. The lithium transition metal composite particle of claim 1 , wherein a doping amount of the zirconium is greater than 0 mol % and equal to or less than 2 mol %.

6. The lithium transition metal composite particle of claim 1 , wherein the LiF is included in an amount of 0.1 wt % to 0.5 wt % based on a total weight of the lithium transition metal composite particles.

7. The lithium transition metal composite particle of claim 1 , wherein the lithium transition metal oxide is any one selected from the group consisting of lithium-cobalt-based oxide, lithium-manganese-based oxide, lithium-nickel-manganese-based oxide, lithium-manganese-cobalt-based oxide, and lithium-nickel-manganese-cobalt-based oxide, or a mixture of two or more thereof.

8. The lithium transition metal composite particle of claim 7 , wherein the lithium transition metal oxide is any one selected from the group consisting of LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , Li(Ni a Co b Mn c )O 2 (where 0<a<1, 0<b<1, 0<c<1, and a+b+c=1), LiNi 1-Y Co Y O 2 , LiCo 1-Y Mn Y O 2 , LiNi 1-Y Mn Y O 2 (where 0≦Y<1), Li(Ni a Co b Mn c )O 4 (where 0<a<2, 0<b<2, 0<c<2, and a+b+c=2), LiMn 2-z Ni z O 4 , and LiMn 2-z Co z O 4 (where 0<z<2), or a mixture of two or more thereof.

9. A cathode active material comprising the lithium transition metal composite particles of claim 1 .

10. A cathode comprising the cathode active material of claim 9 .

11. A lithium secondary battery comprising:

a cathode;

an anode; and

a separator disposed between the cathode and the anode,

wherein the cathode is the cathode of claim 10 .