Lithium Secondary Battery

Provided is a lithium secondary battery including a positive electrode; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte, wherein the positive electrode includes a positive electrode active material, the positive electrode material includes a perlithium manganese-rich oxide containing about 50 mol % or more of Mn based on all metal elements excluding lithium, and having a molar ratio of lithium to all transition metals exceeding about 1, and the non-aqueous electrolyte includes a lithium salt, a compound represented by Chemical Formula 1 and a compound represented by Chemical Formula 2: