| abstract |
The present invention relates to a positive electrode active material for a lithium secondary battery and a lithium secondary battery including the same, wherein the positive electrode active material is a coin-type half cell comprising a lithium metal composite oxide represented by the following formula (1) as a positive electrode and a lithium metal as a negative electrode (Coin The first cycle discharge capacity is 165mAh / g or more in the 4.3 ~ 3.0 V voltage range by the half cell configuration, and the main exotherm temperature by DSC (Differential Scanning Calorimetry) at 4.3V is 300 ℃ or more, and 4.6 It is a lithium metal composite oxide which shows that main heating temperature by DSC at V is 290 degreeC or more, and Ni ion site occupying 3a site is 1.9-3.1 in the Rietveld analysis by X-ray diffraction.n n n The positive electrode active material of the present invention has a high capacity and excellent thermal stability by adjusting the Li / M ratio, NiMnCo ratio and cation mixing degree.n n n Li [Li z A (1-za) D a ] E b O 2 -b ... One)n n n Wherein A = Ni (1-xy) M 1 x Co y ,n n n M 1 is at least one metal element selected from Mn, Ti, and Zr,n n n D is at least one metal element selected from Mg, Al, B, Zn, Ga, and Ge.n n n E is at least one anion selected from P, F, S,n n n -0.05 ≤ z ≤ 0.1, 0 ≤ a ≤ 0.05, 0 ≤ b ≤ 0.05n n n 0.3 ≦ x ≦ 0.4 and 0.85 <2x + y ≦ 0.9. |