LITHIUM SECONDARY BATTERY

The present disclosure provides a lithium secondary battery capable of improving high-temperature durability and cycle characteristics during high-voltage operation. The lithium secondary battery includes a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution for a lithium secondary battery, wherein the positive electrode active material includes a core including a lithium cobalt-based oxide represented by Formula 1; and a shell including a lithium cobalt-based oxide represented by Formula 2 which is disposed on a surface of the core, wherein the core and the shell include at least one doping element selected from the group consisting of Al, Zr, Mg, and Ti, and the non-aqueous electrolyte solution may include a lithium salt, an organic solvent, lithium difluorophosphate, and a dinitrile-based compound represented by Formula 3.