Cathode active material for lithium secondary battery and lithium secondary battery including the same
A cathode active material for a lithium secondary battery includes a lithium-aluminum-titanium oxide formed on a surface of a lithium metal oxide particle having a specific formula. The cathode active material may have an improved structural stability even in a high temperature condition.
1. A cathode active material for a lithium secondary battery, comprising:
a lithium metal oxide particle containing Ni;
an aluminum-zirconium oxide represented as AlZrO formed on at least a part of a surface of the lithium metal oxide particle as a coating of the lithium metal oxide particle; and
a boron-including oxide as an additional coating formed on the coating of the aluminum-zirconium oxide, wherein the boron including oxide includes at least one selected from the group consisting of B 4 O 10 , AlBO 3 and Li 2 B 4 O 7 , and
wherein the lithium metal oxide particle is formed of a crystal of a compound represented by Formula 1 below:
Li α Ni y M z O 2-β Formula 1
wherein, in the above Formula 1, M is at least one element selected from the group consisting of Co, Mn, Ti, Zr, Al and B, and α, β, y, and z are in a range of 0.7≤α ≤1.1, −0.1≤β≤ 0.5, 0.7≤y≤0.95, and 0.95<y+z≤1.1, respectively.
2. The cathode active material for a lithium secondary battery according to claim 1 , further comprising a lithium-aluminum-titanium oxide formed on at least a part of the surface of the lithium metal oxide particle.
3. The cathode active material for a lithium secondary battery according to claim 2 , wherein the lithium-aluminum-titanium oxide is represented by Formula 2 below:
Li γ Al v Ti w O x [Formula 2]
wherein, in the above Formula 2, γ, v, w and x are in a range of 0.8<γ≥1.2, 0<v<1, 0 <w≤ 1, 0.98≤v+w≤ 1.02, and 1.5≤x≤4, respectively.
4. The cathode active material for a lithium secondary battery according to claim 1 , wherein, in the above Formula 1, M z is Co a Mn b M′ c , M′ is at least one element selected from the group consisting of Ti, Zr, Al and B, and a, b, c, and y are in a range of 0.05≤a≤0.2, 0.03≤b≤0.2, and 0.95<y+a+b+c≤1.1, respectively.
5. The cathode active material for a lithium secondary battery according to claim 1 , further comprising at least one of Al 2 O 3 and LiAlO 2 formed on the surface of the lithium metal oxide particle.
6. The cathode active material for a lithium secondary battery according to claim 1 , further comprising LiTiO 2 formed on the surface of the lithium metal oxide particle.