Lithium secondary battery

A lithium secondary battery, comprising:

• a cathode comprising a cathode current collector and a cathode active material layer disposed on at least one surface of the cathode current collector, the cathode active material layer comprising a cathode active material including first cathode active material particles, each of which has a single particle shape;
• an anode facing the cathode;
• and
• a non-aqueous electrolyte comprising a non-aqueous organic solvent that contains a fluorine-based organic solvent, a lithium salt and an additive,
• wherein the cathode active material further comprises second cathode active material particles, each of which has a secondary particle shape, and a content of the first cathode active material particles based on a total weight of the cathode active material is in a range from 10 wt % to 40 wt %,
• wherein the non-aqueous organic solvent further comprises a non-fluorine-based organic solvent,
• wherein a volume ratio of the fluorine-based organic solvent to the non-fluorine- based organic solvent is in a range from 1.5 to 9,
• wherein the volume ratio is defined as a ratio of a total volume of the fluorine-based organic solvent to a total volume of the non-fluorine-based organic solvent,
• wherein the non-fluorine-based organic solvent includes at least one selected from the group consisting of a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent and an aprotic solvent,
• wherein the fluorine-based organic solvent includes a monofluoro-based organic solvent and a difluoro-based organic solvent,
• wherein the monofluoro-based organic solvent is represented by Chemical Formula 2:
• wherein, in Chemical Formula 2, R1 is a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C6-C12 aryl group, a substituted or unsubstituted C5-C12 cycloalkyl group, a substituted or unsubstituted C5-C12 cycloalkenyl group, a substituted or unsubstituted 5 to 7 membered heterocycloalkyl group, or a substituted or unsubstituted 5 to 7 membered heterocycloalkenyl group, and
• wherein the difluoro-based organic solvent is represented by Chemical Formula 3:
• wherein, in Chemical Formula 3, R2 is a hydrocarbon containing a substituted or unsubstituted C1-C6 kyl group or a substituted or unsubstituted C6-C12 aryl group, and R3 is a hydrocarbon including a substituted or unsubstituted C1-C6 alkyl group or a substituted or unsubstituted C2-C6 alkenyl group.