Cathode active material precursor for lithium secondary battery, cathode active material for lithium secondary battery and lithium secondary battery
A cathode active material precursor for a lithium secondary battery has a structure of a nickel composite hydroxide. An oxygen position in a Z-axis direction measured by a Rietveld method in a space group P-3m crystal structure based on an X-ray diffraction (XRD) analysis is 0.200 or more. A cathode active material and a lithium secondary battery having a stabilized crystal structure are provided using the cathode active material precursor.
1 . A cathode active material precursor for a lithium secondary battery having a structure of a nickel composite hydroxide,
wherein an oxygen position in a Z-axis direction measured by a Rietveld method in a space group P-3m crystal structure based on an X-ray diffraction (XRD) analysis is 0.200 or more.
2 . The cathode active material precursor for a lithium secondary battery of claim 1 , wherein the structure of the nickel composite hydroxide is represented by Chemical Formula 1:
Ni 1−x−y−z Co x Mn y M z (OH) 2+a [Chemical Formula 1]
wherein, in Chemical Formula 1, M includes at least one selected from the group consisting of Mg, Sr, Ba, B, Al, Si, Ti, Zr and W, 0.02≤x≤0.15, 0≤y≤0.15, 0≤z≤0.1, and −0.5≤a≤0.1.
3 . The cathode active material precursor for a lithium secondary battery of claim 1 , wherein a molar ratio of nickel among elements other than a hydroxyl group is 0.8 or more.
4 . The cathode active material precursor for a lithium secondary battery of claim 1 , wherein the oxygen position in the Z-axis direction is 0.213 or more.
5 . The cathode active material precursor for a lithium secondary battery of claim 1 , wherein the oxygen position in the Z-axis direction is in a range from 0.210 to 0.240.
6 . A cathode active material for a lithium secondary battery having a structure of a lithium-nickel-based composite oxide,
wherein a first sum of full widths at maximum defined by Equation 1 is 1.7 or more:
First sum of full widths at half maximum= H (101)+ H (102)+ H (104)/ H (003)+ H (006) [Equation 1]
wherein, in Equation 1, H(101), H(102), H(104), H(003) and H(006) are each a full width at half maximum corresponding to a (101) plane, a (102) plane, a (104) plane, a (003) plane and a (006) plane, respectively, by an X-ray diffraction (XRD) analysis.
7 . The cathode active material for a lithium secondary battery of claim 6 , wherein the lithium-nickel-based composite oxide is represented by Chemical Formula 2:
Li b Ni 1−x−y−z Co x Mn y M z (OH) 2+a [Chemical Formula 2]
wherein, in Chemical Formula 2, 0.02≤x≤0.15, 0≤y≤0.15, 0≤z≤0.1, −0.5≤a≤0.1, 0.9≤b≤1.2, and
M includes at least one selected from the group consisting of Mg, Sr, Ba, B, Al, Si, Ti, Zr and W.
8 . The cathode active material for a lithium secondary battery of claim 6 , wherein the first sum of full widths at maximum is 1.8 or more.
9 . The cathode active material for a lithium secondary battery of claim 6 , wherein the first sum of full widths at maximum is in a range from 1.7 to 2.2.
10 . The cathode active material for a lithium secondary battery of claim 6 , wherein a second sum of full widths at maximum defined by Equation 2 is 2.0 or more:
second sum of full widths at half maximum= H (101)+ H (102)/ H (006). [Equation 2]
11 . The cathode active material for a lithium secondary battery of claim 10 , wherein the second sum of full widths at maximum is in a range from 2.1 to 2.5.
12 . A lithium secondary battery, comprising:
a cathode comprising a cathode active material layer that comprises the cathode active material for a lithium secondary battery of claim 6 ; and
an anode facing the cathode.