Lithium Secondary Battery

The present disclosure relates to a lithium secondary battery comprising a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte. The non-aqueous electrolyte includes an organic solvent, a lithium salt, a coumarin-based compound represented by [Chemical Formula 1], and a halogen-substituted cyclic carbonate, and the positive electrode active material includes a lithium manganese-rich oxide represented by [Chemical Formula 2].