Detailed description of the invention Technical challenge [16] In the present invention, by including a non-aqueous electrolyte capable of forming a solid film on the electrode surface, it is intended to provide a lithium secondary battery capable of securing capacity characteristics even at high temperature storage. Means of solving the task [17] In order to solve the above problem, in one embodiment of the present invention [18] A positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, [19] The positive electrode includes a positive electrode active material represented by Formula 1 below, [20] The non-aqueous electrolyte contains a non-aqueous organic solvent, a lithium salt, and an additive, [21] The additive provides a lithium secondary battery as a mixed additive comprising lithium difluorophosphate (LiDFP), tetravinylsilane (TVS), and a sultone compound in a weight ratio of 1:0.05:0.1 to 1:1:1.5. [22] [Formula 1] [23] Li(Ni a Co b Mn c )O 2 [24] In Formula 1, [25] 0.65