Positive electrode material for secondary battery and lithium secondary battery comprising same

A positive electrode material for a secondary battery, the positive electrode material comprising a first positive electrode active material and a second positive electrode active material, the first positive electrode active material and the second positive electrode active material being single-particle-types and lithium composite transition metal oxides comprising nickel, cobalt, and manganese and having a nickel content accounting for 60 mol % or more of total metals except for lithium,

• wherein the first positive electrode active material has a mean particle diameter (D50) of 3 μm or less and a molar ratio (Li/M) of lithium to the metals (M) except for lithium of 1.10 to 1.20,
• wherein the second positive electrode active material has a mean particle diameter (D50) of greater than 3 μm and a molar ratio (Li/M) of lithium to the metals (M) except for lithium of 1.00 to 1.13,
• wherein the molar ratio (Li/M) of the first positive electrode active material is different than the molar ratio (Li/M) of the second positive electrode active material, and
• wherein a single-particle-type positive electrode material consists of one primary particle or an agglomeration of ten or less primary particles.