CATHODE ACTIVE MATERIAL WITH HIGH CAPACITY AND LITHIUM SECONDARY BATTERY COMPRISING THEREOF

摘要

PURPOSE: A positive electrode active material is provided to provide a high capacity by a unique structure change in an initial charging and discharging process and to provide excellent lifetime performance, thereby obtaining a lithium secondary battery with excellent performance. CONSTITUTION: A positive electrode active material comprises a lamellar lithium-manganese oxide. In the lamellar lithium-manganese oxide, the content of Mn is higher than the content of other transition metals. The content of Li is 1 mol or more based on 1 mol of the lithium transition metal oxide. The lamellar lithium-manganese oxide has a flat voltage characteristic that oxygen is emitted together with lithium deintercalation during initial charging in a high voltage range of 4.4V or more. After the initial charging, for improving electric conductivity, the lithium-manganese oxide includes different kinds of carbon-based conductive material in a voltage range of 3.5V or more. [Reference numerals] (AA) Embodiment; (BB) Comparative embodiment