Positive electrode active material for lithium secondary battery, method of preparing the same, and positive electrode for lithium secondary battery and lithium secondary battery which include the positive electrode active material

A positive electrode active material comprising:

• a nickel-containing lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of transition metals excluding lithium;
• and
• a lithium-containing inorganic compound layer formed on a surface of the nickel-containing lithium transition metal oxide,
• wherein the positive electrode active material has a first peak in a range of 5 eV or less, a second peak in a range of 7 eV to 13 eV, and a third peak in a range of 20 eV to 30 eV when intensity is measured by X-ray photoelectron spectroscopy, and the first peak has a maximum value of 80% to 120% with respect to the third peak, and
• wherein the nickel-containing lithium transition metal oxide is represented by Formula 1:
• Li1+a(NibCocXdM1e)1−aO2 [Formula 1]
• wherein, in Formula 1,
• X is at least one selected from the group consisting of manganese (Mn) and aluminum (Al),
• M1 is at least one selected from the group consisting of zirconium (Zr), boron (B), cobalt (Co), Al, tungsten (W), magnesium (Mg), cerium (Ce), tantalum (Ta), titanium (Ti), strontium (Sr), barium (Ba), hafnium (Hf), fluorine (F), phosphorus (P), lanthanum (La), and yttrium (Y), and
• 0≤a≤0.1, 0.6≤b≤1.0, 0≤c≤0.3, 0≤d≤0.3, and 0≤e≤0.1.