Cathode active material, and cathode and lithium battery including the material

1. A cathode active material comprising a lithium metal oxide represented by Formula 1:

Li[Li x Me y M′ z ]O (2+d)   Formula 1

wherein

x+y+z=1, 0<x<0.33, 0<z≦0.1, and 0≦d≦0.1,

Me is at least one metal selected from Mn, V, Cr, Fe, Co, Ni, Al and B, and

M′ is [at least one metal selected from] Sc[, and Y].

2. The cathode active material of claim 1 , wherein z satisfies the inequality 0.005≦z≦0.05.

3. The cathode active material of claim 1 , wherein Me comprises:

at least one metal selected from V, Cr, Fe, Co, Ni, Al, and B; and

Mn.

4. The cathode active material of claim 1 , wherein an amount of Mn is in a range of about 20 to about 80 mole percent, based on a total number of moles of [Li x Me y M′ z ] in the lithium metal oxide of Formula 1.

5. The cathode active material of claim 1 , wherein the lithium metal oxide is represented by Formula 3:

Li[Li x Ni a Co b Mn c M′ z ]O (2+d)   Formula 3

wherein x+a+b+c+z=1, 0<x<0.33, 0<z≦0.1,0<a≦0.5, 0<b≦0.5, 0.2≦c≦0.8, and 0≦d≦0.1, and

M′ is Sc [or Y].

6. The cathode active material of claim 5 , wherein z satisfies the inequality 0.005≦z≦0.05.

7. The cathode active material of claim 1 , wherein the lithium metal oxide is represented by Formula 4:

Li[Li x Ni a Co b Mn c M′ z ]O (2+d)   Formula 4

wherein x+a+b+c+z=1, 0.1<x<0.2, 0<z≦0.1,0<a≦0.3, 0<b≦0.3, 0.4≦c≦0.6, and 0≦d≦0.1, and

M′ is Sc [or Y].

8. The cathode active material of claim 7 , wherein z satisfies the condition of 0.005≦z≦0.05.

9. The cathode active material of claim 1 , wherein the lithium metal oxide is represented by Formula 5:

Li[Li x Ni a Co b Mn c Sc z ]O (2+d)   Formula 5

wherein x+a+b+c+z=1, 0.1<x<0.2, 0.005≦z≦0.1, 0<a≦0.3, 0<b≦0.3, 0.4≦c≦0.6, and 0≦d≦0.1.

10. A cathode comprising the cathode active material of claim 1 .

11. A lithium battery comprising the cathode of claim 10 .