Patent ID: 7481991

Claim:
A process for producing a lithium-containing composite oxide for a lithium secondary battery comprising: impregnating an N element source powder with an aqueous solution comprising a carboxylic acid having two or more carboxylic acid groups or carboxylic acid groups and hydroxyl groups and an M element or its salt; drying a slurry of the N element source powder impregnated with the aqueous solution comprising a carboxylic acid having two or more carboxylic acid groups or carboxylic acid groups and hydroxyl groups and an M element or its salt; mixing a lithium source, the dried slurry of the N element impregnated with the carboxylic acid and M element and optionally, a fluorine source; and firing the mixture at from 950° C. to 1050° C.; wherein the lithium-containing composite oxide is represented by the formula: Li p N x M y O z F a wherein N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Sn, Zn, Al, alkaline earth metal elements, and transition metal elements other than N, 0.9≦p≦1.1, 0.97≦x<1.00, 0<y≦0.03, 1.9≦z≦2.1, x+y=1, 0≦a≦0.02, the N element source powder has an average particle size (D 50 ) of from 2 to 20 μm, and the M element and optionally fluorine are present on the surface of particles of the lithium-containing composite oxide.