Lithium composite oxide and lithium secondary battery comprising the same

A lithium composite oxide, comprising:

• primary particles enabling lithium intercalation and deintercalation and comprising at least nickel (Ni), cobalt (Co) and manganese (Mn), and secondary particles in which the primary particles are aggregated;
• and
• a coating layer having a boron (B)-containing oxide, which covers at least a part of a region selected from the interface between the primary particles and the surface of the secondary particle,
• wherein a full width at half-maximum (FWHM;
• deg., 2θ) range of a (104) peak among XRD peaks defined by the hexagonal lattice with an R-3m space group is represented by Expression 1 below:
• −0.025≤FWHM(104)−{0.04+(q−0.6)×0.25}≤0.025 [Expression 1]
• In Expression 1, q is a molar ratio of nickel with respect to the total molar ratio of metal elements excluding lithium in the primary particle, and the FWHM(104) is represented by Expression 2 below,
• FWHM(104)=FWHMLi(104)−FWHMSi(220) [Expression 2]
• In Expression 2,
• the FWHMLi(104) indicates the FWHM of a (104) peak observed at 44.5±1.0° (2θ) among XRD measurement values of the lithium composite oxide, and
• the FWHMSi(220) indicates the FWHM of a (220) peak observed at approximately 47.3+1.0° (2θ) among XRD measurement values of an Si powder,
• wherein the amount of Co and Mn in relation to the total amount of Co, Mn and Ni in the lithium composite oxide is from 6 to 40 mol % and the amount of a dopant other than Co, Mn and Ni in the lithium composite oxide is 2,719 ppm or less.