HIGH-CAPACITY CATHODE ACTIVE MATERIAL AND LITHIUM SECONDARY BATTERY INCLUDING SAME

摘要

The present invention relates to a cathode active material including a lithium manganese-based oxide. Particularly, the present invention relates to a cathode active material characterized in that the lithium manganese-based oxide has a layered crystalline structure; Mn is higher in content than (an)other transition metal(s); 1 mol or more of Li is included for 1 mol of a lithium-transition metal oxide; there is a flat level characteristic in which oxygen is released together with release of lithium during first charging in a high voltage range of 4.4V or higher; domains exhibiting electrochemical activity due to a structural change in a voltage range of 3.5V or lower after the first charging are included the layered crystalline structure; and a conductive material is included to improve the electrical conductivity of the lithium manganese-based oxide in the voltage range of 3.5V or lower after the first charging.