Lithium secondary battery comprising electrolyte

A lithium secondary battery, comprising:

• a positive electrode;
• a silicon-based negative electrode;
• a separator provided between the positive electrode and the negative electrode;
• and
• an electrolyte,
• wherein the silicon-based negative electrode comprises a negative electrode current collector layer;
• and a negative electrode active material layer provided on one surface or both surfaces of the negative electrode current collector layer,
• wherein the negative electrode active material layer comprises a negative electrode active material layer composition,
• wherein the negative electrode active material layer composition comprises a silicon-based active material, and the silicon-based active material comprises one or more selected from the group consisting of silicon, SiOx, wherein 0<x<2, SiC, and a Si alloy,
• wherein the electrolyte comprises an additive,
• wherein the additive comprises:
• a bifunctional electrolyte additive;
• and an additive comprising two or more fluoro groups,
• wherein the bifunctional electrolyte additive comprises a cyano group and a coumarin group as functional groups, and
• wherein 45 parts by weight or more and 55 parts by weight or less of the bifunctional electrolyte additive;
• and 45 parts by weight or more and 55 parts by weight or less of the additive comprising two or more fluoro groups are comprised based on 100 parts by weight of the additive.