Cathode active material precursor and lithium secondary battery utilizing same
A cathode active material precursor according to embodiments of the present invention includes nickel (Ni) and cobalt (Co) and includes an excess amount of Ni. A 101 /A 001 is 1 or more and I 101 /I 001 is 1 or more. A 101 is a peak area of (101) plane, and A 001 is a peak area of (001) plane by an X-ray diffraction (XRD) analysis, and I 101 is a peak intensity of (101) plane, and I 001 is a peak intensity of (001) plane by the XRD analysis. A cathode and a lithium secondary battery having improved crystallinity and long-term stability using the cathode active material precursor.
1 . A cathode active material precursor comprising Chemical Formula 1,
Ni 1−x−y−z Co x Mn y M z (OH) 2+a [Chemical Formula 1]
wherein 0.02≤x≤0.15, 0<y≤0.15, 0≤z≤0.1, 0.75≤1−x−y−z≤0.95, −0.5≤a≤0.1, and M includes at least one of Mg, Sr, Ba, B, Al, Si, Mn, Ti, Zr or W,
wherein A 101 /A 001 is 1 or more and I 101 /I 001 is 1 or more, and
A 101 is a peak area of (101) plane and A 001 is a peak area of (001) plane by an X-ray diffraction (XRD) analysis, and I 101 is a peak intensity of (101) plane and I 001 is a peak intensity of (001) plane by the XRD analysis.
2 . The cathode active material precursor according to claim 1 , wherein A 101 /A 001 is in a range from 1 to 2.
3 . The cathode active material precursor according to claim 1 , wherein I 101 /I 001 is in a range from 1 to 2.
4 . The cathode active material precursor according to claim 1 , wherein a molar content of Co is greater than a molar content of Mn.
5 . A cathode active material obtained from the cathode active material precursor according to claim 1 .
6 . The cathode active material according to claim 5 , wherein the cathode active material is represented by Chemical Formula 2:
Li 1+b Ni 1−x−y−z Co x Mn y M z O 2+c [Chemical Formula 2]
wherein, in Chemical Formula 2, −0.05≤b≤0.15, 0.02≤x≤0.15, 0<y≤0.15, 0≤z≤0.1, −0.5≤c≤0.1, and M includes at least one of Mg, Sr, Ba, B, Al, Si, Mn, Ti, Zr or W.
7 . The cathode active material according to claim 5 , wherein a length of a major axis of a primary particle is 1.5 to 7 times a length of a minor axis of the primary particle.
8 . A lithium secondary battery comprising:
a cathode including a cathode active material obtained from the cathode active material precursor according to claim 1 ;
an anode; and
a separation layer disposed between the cathode and the negative anode.