Cathode active material for lithium secondary battery, and lithium secondary battery comprising same

1. A positive active material for a lithium secondary battery comprises lithium, nickel, cobalt, manganese, and a doping element,

wherein the doping element includes Zr, Al, and Ti,

wherein the positive active material for the lithium secondary battery is represented by Chemical Formula 1 below:

Li a1 [Ni x1 Co y1 Mn z1 ] t1 (Zr h1 Al g1 Ti u1 )O 2-p X1 p   [Chemical Formula 1]

in Chemical Formula 1,

X1 is at least one element selected from a group including F, N, and P,

a1 is 0.8≤a1≤1.3,

t1 is 0.9580<t1<0.9915, and

0.6≤x1≤0.95, 0<y1≤0.2, 0<z1≤0.2, 0.0010≤h1≤0.005, 0.007≤g1≤0.033, 0.0005≤ul≤0.004, and 0≤p≤0.02.

2. The positive active material for the lithium secondary battery of claim 1 , wherein

the doping element further includes W.

3. The positive active material for the lithium secondary battery of claim 2 , wherein

the doping ratio of W is 0.03 mol % to 0.1 mol % with respect to 100 mol % of nickel, cobalt, manganese, and the doping element.

4. The positive active material for the lithium secondary battery of claim 2 , wherein

the positive active material for the lithium secondary battery is represented by Chemical Formula 2 below:

Li a2 [Ni x2 Co y2 Mn z2 ] t2 (Zr h2 Al g2 W j Ti u2 )O 2-p X2 p   [Chemical Formula 2]

in Chemical Formula 2,

X2 is at least one element selected from a group including F, N, and P,

a2 is 0.8≤a2≤1.3,

t2 is 0.9570≤t2≤0.9912, and

0.6≤x2≤0.95, 0<y2≤0.2, 0<z2≤0.2, 0.001≤h2≤0.005, 0.007≤g2≤0.033, 0.0003≤j≤0.001, 0.0005≤u2≤0.004, and 0≤p≤0.02.

5. The positive active material for the lithium secondary battery of claim 1 , wherein

the positive active material for the lithium secondary battery has a ratio I (003)/I (104) of a peak intensity on a 003 plane to a peak intensity on a 104 plane of 1.1 to 1.2 when measuring an X-ray diffraction pattern.

6. The positive active material for the lithium secondary battery of claim 1 , wherein

for the positive active material for the lithium secondary battery, when measuring an X-ray diffraction pattern, an a-axis length (La) is 2.8500 Å to 2.8800 Å, a c-axis length (Lc) is 14.1800 Å to 14.2900 Å, and a distance ratio (c/a) between a crystal axis of the c-axis length to the a-axis length is 4.93 to 5.0.

7. The positive active material for the lithium secondary battery of claim 1 , wherein

for the positive active material for the lithium secondary battery when measuring an X-ray diffraction pattern,

an average grain size (a crystalline size, Lc) is 80 nm to 140 nm,

and an R-factor value represented by Equation 1 is 0.52 to 0.55,

R-factor={I 006+I 102}/I 101  [Equation 1].

8. A lithium secondary battery comprising:

a positive electrode including a positive active material of claim 1 ;

a negative electrode; and

a non-aqueous electrolyte.