Patent ID: 7846586

Claim:
An active material for a positive electrode of a lithium secondary battery, comprising a lithium-nickel composite oxide of the general formula Li x (Ni 1-y Co y ) 1-z M z O 2 , where: 0.98≦x≦1.10; 0.05≦y≦0.4; 0.01≦z≦0.2; and M is chosen from at least one element among Al, Zn, Ti, and Mg, wherein: a. according to Rietveld analysis, the Li site occupancy rate for Li sites in a crystal of the lithium-nickel composite oxide is 98% or greater; b. the average particle size of spherical secondary particles of lithium-nickel composite oxide ranges from 5 μm to 15 μm; and c. the difference between the specific surface area of the active material before and after a washing process, the washing process being performed for assessing characteristics of the secondary particles as an index, is 1.07 m 2 /g or less.