Cathode active material exhibiting improved property in high voltage

A cathode active material comprising:

• a lithium transition metal oxide based on at least one transition metal selected from the group consisting of Ni, Mn and Co, wherein the lithium transition metal oxide contains fluorine, 50 to 99.9% of a total weight of fluorine contained in the active material is present on a surface of the lithium transition metal oxide, and at least one metal selected from a group consisting of Mg, Ti, Zr, Al and Fe as well as sulfur (S) are further contained in the lithium transition metal oxide,
• wherein a content of the sulfur ranges from 0.005 to 5 wt. % relative to a total weight of the lithium transition metal oxide,
• wherein the lithium transition metal oxide is represented by the following Formula 1:
• Li1+aMn(1-w-x-y-z)NiwCoxD1y(D2,D3)ZO2*D1′y(D2′,D3′)Z′ (1)
• wherein, −0.3≦a≦0.3;
• 0≦w<0.8;
• 0<x<0.8;
• 0.001<y<0.02;
• 0.005<z<0.1;
• 0≦(1−w−x−y−z)<0.5;
• D1 is fluorine;
• D2 is at least one or two selected from a group consisting of Mg, Ti, Zr, Al and Fe;
• D3 is sulfur;
• y denotes a doping amount of D1;
• z denotes the sum of doping amounts of D2 and D3;
• D1′, D2′ and D3′ denote D1, D2 and D3 present on the surface of the lithium transition metal oxide, respectively;
• y′ denotes a coating amount of D1, provided that the sum of y′ and y ranges from 0.01 to 7 wt. % relative to a total weight of lithium transition metal oxide;
• and
• z′ denotes the sum of coating amounts of D2′ and D3′, provided that the sum of z′ and z ranges from 0.01 to 10 wt. % relative to a total weight of lithium transition metal oxide.