Lithium Secondary Battery Having Improved High-Temperature Storage Characteristics

A lithium battery is disclosed herein. In some embodiments, a lithium secondary battery includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution, wherein the positive electrode includes a positive electrode active material represented by Formula 1, and the non-aqueous electrolyte solution includes a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive is a mixed additive which includes lithium difluorophosphate, tetravinylsilane, and a sultone compound in a weight ratio of 1:0.05:0.1 to 1:1:1.5: Li(NiCoMn)O [Formula 1]