Lithium secondary battery

A lithium secondary battery comprising:

• a cathode including a cathode active material;
• an anode;
• and
• an electrolyte disposed between the cathode and the anode,
• wherein the cathode active material has a charge cut-off voltage of about 4.2 Volts to about 10 Volts with respect to a lithium counter electrode, and
• wherein the electrolyte comprises an organic fluorinated ether compound, an organic solvent, a lithium salt, and an additive to form a solid electrolyte interface membrane, wherein the organic fluorinated ether compound is represented by Formulae 2 to 14
• Formula 2
• R11—CF2—CH2—O—CFH—CFH—R12
• Formula 3
• R11—CFH—CH2—O—CFH—CF2—R12
• Formula 4
• R11—CF2—CH2—O—CFH—CF2—R12
• Formula 5
• CF3—CH2—O—CFH—CFH—R12
• Formula 6
• R11—CF2—CH2—O—CFH—CF3
• Formula 7
• CF3—CH2—O—CFH—CF2—R12
• Formula 8
• R21—CH2—O—CF2—CFH—R12
• Formula 9
• R21—CH2—O—CF2—CF2—R12
• Formula 10
• R11—CFH—CH2—O—CF2—R22
• Formula 11
• R11—CF2—CH2—O—CF2—R22
• Formula 12
• R21—CFH—O—CFH—R22
• Formula 13
• R21—CFH—O—CF2—R22
• Formula 14
• R21—CF2—O—CF2—R22
• wherein, in Formulae 2 to 7, 12, and 13,
• R11 is hydrogen, fluorine, a C1-C8 alkyl group, a C3-C8 cycloalkyl group, a C1-C8 fluorinated alkyl group, or a C3-C8 fluorinated cycloalkyl group;
• R21 is hydrogen, fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C1-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• R12 is hydrogen, fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C1-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• and
• R22 is hydrogen, fluorine, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C1-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group,
• wherein in Formula 8,
• R21 is hydrogen, fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C3-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• and
• R12 is hydrogen, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C2-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• wherein in Formula 9,
• R21 is fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C1-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• and
• R12 is fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C1-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• wherein in Formula 10,
• R11 is hydrogen, a C1-C8 alkyl group, a C3-C8 cycloalkyl group, a C1-C8 fluorinated alkyl group, or a C3-C8 fluorinated cycloalkyl group;
• and
• R22 is hydrogen, fluorine, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C1-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group;
• wherein in Formula 11,
• R11 is hydrogen, fluorine, a C1-C8 alkyl group, a C3-C8 cycloalkyl group, a C3-C8 fluorinated alkyl group, or a C3-C8 fluorinated cycloalkyl group;
• and
• R22 is hydrogen, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C4-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group;
• and
• wherein in Formula 14,
• R21 is hydrogen, fluorine, a C1-C9 alkyl group, a C3-C9 cycloalkyl group, a C2-C9 fluorinated alkyl group, or a C3-C9 fluorinated cycloalkyl group;
• and
• R22 is hydrogen, fluorine, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C3-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group,
• wherein the organic solvent comprises an ether solvent, an ester solvent, an amide solvent, a linear carbonate solvent, a cyclic carbonate solvent, or a combination thereof, wherein an anion of the lithium salt is F−, Cl−, Br, I−, NO3−, N(CN)2−, BF4−, ClO4−, PF6−, (CF3)2PF4−, (CF3)3PF3−, (CF3)4PF2−, (CF3)5PF−, (CF3)6P−, CF3SO3−, CF3CF2SO3−, CF3CF2(CF3)2CO−, (CF3SO2)2N−, (FSO2)2N−, (CF3SO2)2CH−, (SF5)3C−, (CF3SO2)3C−, CF3(CF2)7SO3−, CF3CO2−, CH3CO2−, SCN−, (CF3CF2SO2)2N−, or a combination thereof, and
• wherein the additive to form a solid electrolyte interface membrane is vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, a cyclic sulfite, a saturated sultone, an unsaturated sultone, an acyclic sulfone, or a combination thereof.