Non-aqueous electrolyte solution for lithium secondary battery and lithium secondary battery including the same

A lithium secondary battery, comprising:

• a positive electrode;
• a negative electrode;
• a separator, and
• a non-aqueous electrolyte solution;
• wherein the positive electrode having a positive electrode active material,
• wherein the positive electrode active material comprises a lithium transition metal oxide represented by Formula 2, and
• wherein the non-aqueous electrolyte solution comprises:
• lithium bis(fluorosulfonyl)imide as a first lithium salt;
• a second lithium salt;
• an organic solvent;
• a compound represented by the following Formula 1,
• wherein a molar ratio of the first lithium salt to the second lithium salt is in a range of 1:1.2 to 1:1.4, and
• wherein the compound represented by Formula 1 is included in an amount of 0.1 wt % to 1 wt % based on a total weight of the non-aqueous electrolyte solution:
• [Formula 2]
• Li(NiaCobMnc)O2
• wherein, in Formula 2,
• 0.7≤a≤0.9, 0.05≤b<0.3, 0.05≤c<0.3, and a+b+c=1.