Electrolyte for lithium secondary battery and lithium secondary battery including the electrolyte

1. An electrolyte for a lithium secondary battery, the electrolyte comprising:

a compound represented by Formula 1;

a lithium salt; and

an organic solvent,

wherein an amount of the compound represented by Formula 1 is about 0.1 weight percent to about 3.0 weight percent, based on a total weight of the electrolyte, and wherein the electrolyte further comprises a disultone compound represented by Formula 7:

wherein, in Formula 1, R 1 to R 15 are each independently hydrogen, fluorine, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C6-C10 aryl group, or a combination thereof,

wherein when at least one of R 1 to R 15 is hydrogen, at least one of R 1 to R 15 is fluorine, a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group, and

wherein when at least one of R 1 to R 15 is fluorine, at least one of R 1 to R 15 is hydrogen, a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group,

wherein, in Formula 7,

R 1 and R 2 are each independently a substituted C1-C30 alkylene group or an unsubstituted C1-C30 alkylene group, and

a substituent of the substituted C1-C30 alkylene group is at least one of a halogen, a methyl group, an ethyl group, an n-proply group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, a vinyl group, a propinyl group, a butynyl group, a propenyl group, or a butenyl group.

2. The electrolyte of claim 1 , wherein the amount of the compound represented by Formula 1 is about 0.1 weight percent to about 2.9 weight percent, based on the total weight of the electrolyte.

3. The electrolyte of claim 1 , wherein the compound represented by Formula 1 is a compound represented by Formula 2:

wherein, in Formula 2,

R 3 , R 8 , and R 13 are each independently selected from hydrogen, fluorine, and a methyl group.

4. The electrolyte of claim 1 , wherein the compound represented by Formula 1 is a compound represented by at least one of Formula 3, Formula 4, Formular 5, Formula 6 , Formula 6a, or Formula 6b:

5. The electrolyte of claim 1 , wherein the disultone compound represented by Formula 7 is a disultone compound represented by Formula 7a-1 to 7a-4, and

an total amount of the disultone compound represented by Formula 7a-1 to 7a-4 is about 0.5 weight percent to about 2 weight percent, based on the total weight of the electrolyte:

6. The electrolyte of claim 1 , wherein a concentration of the lithium salt is about 0.1 moles per liter to about 5.0 moles per liter.

7. The electrolyte of claim 6 , wherein the lithium salt is at least one of LiPF 6 , LiBF 4 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 2 N, LiC 4 F 9 SO 3 , Li(FSO 2 ) 2 N, LiN(SO 2 CF 2 CF 3 ) 2 , a compound represented by Formula 8, a compound represented by Formula 9, a compound represented by Formula 10, or a compound represented by Formula 11:

8. The electrolyte of claim 6 , wherein

the lithium salt is at least of LiPF 6 , Li(FSO 2 ) 2 N, or a compound represented by Formula 11, and

the concentration of the lithium salt is about 0.8 moles per liter to about 2 moles per liter:

9. A lithium secondary battery comprising:

a positive electrode;

a negative electrode; and

the electrolyte of claim 1 , disposed between the positive electrode and the negative electrode.

10. The lithium secondary battery of claim 9 , wherein the positive electrode comprises a nickel-rich lithium-nickel composite oxide containing about 70 mole percent to about 95 mole percent of nickel, based on a total molar amount of transition metals in the nickel-rich lithium-nickel composite oxide.

11. The lithium secondary battery of claim 10 , wherein the nickel-rich lithium-nickel composite oxide is a compound represented by Formula 14:

Li a Ni x Co y Mn z M c O 2-b A b   Formula 14

wherein, in Formula 14,

M is at least one of vanadium, magnesium, gallium, silicon, tungsten, molybdenum, iron, chromium, copper, zinc, titanium, aluminum, and boron,

A is at least one of F, S, Cl, or Br, and

1.0≤a≤1.2, 0.7≤x<1, 0≤y<1, 0≤z<1, 0≤c<1, x+y+z+c=1, and 0≤b≤0.2.

12. The lithium secondary battery of claim 11 , wherein the nickel-rich lithium-nickel composite oxide is a compound represented by Formula 14a or Formula 14b:

LiNi x Co y Mn z O 2   Formula 14a

LiNi x Co y Al z O 2   Formula 14b

wherein, in Formula 14a and Formula 14b,

0.8≤x≤0.95, 0<y≤0.2, and 0<z≤0.1.

13. The lithium secondary battery of claim 9 , wherein the negative electrode comprises at least one of a silicon compound, a carbonaceous material, a composite of a silicon compound and a carbonaceous material, and a silicon oxide of the formula SiO x , wherein 0<x<2.

14. The lithium secondary battery of claim 9 , wherein a direct current internal resistance of the lithium secondary battery after 300 cycles of charging and discharging is about 165% to about 112% than a direct current internal resistance of the lithium secondary battery after 1 cycle of charging and discharging, as measured at about 45° C.

15. A lithium secondary battery comprising:

a positive electrode comprising a nickel-rich lithium-nickel composite oxide containing about 70 mole percent to about 95 mole percent of nickel, based on a total molar amount of transition metals in the nickel-rich lithium-nickel composite oxide;

a negative electrode; and

an electrolyte disposed between the positive electrode and the negative electrode, the electrolyte comprising

a lithium salt,

an organic solvent,

a compound represented by Formula 1, wherein an amount of the compound represented by Formula 1 is about 0.1 weight percent to less than about 3 weight percent, based on a total weight of the electrolyte, and

wherein the electrolyte further comprises a disultone compound represented by Formula 7:

wherein, in Formula 1, R 1 to R 15 are each independently hydrogen, fluorine, a substituted or unsubtituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group,

wherein, in Formula 7,

R 1 and R 2 are each independently a substituted C1-C30 alkylene group or an unsubstituted C1-C30 alkylene group, and

a substituent of the substituted C1-C30 alkylene group is at least one of a halogen, a methyl group, an ethyl group, an n-proply group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, a vinyl group, a propinyl group, a butynyl group, a propenyl group, or a butenyl group.

16. The lithium secondary battery of claim 15 , wherein the nickel-rich lithium-nickel composite oxide is a compound represented by Formula 14:

Li a Ni x Co y Mn z M c O 2-b A b   Formula 14

wherein, in Formula 14,

M is at least one of vanadium, magnesium, gallium, silicon, tungsten, molybdenum, iron, chromium, copper, zinc, titanium, aluminum, or boron,

A is at least one of F, S, Cl, or Br, and 1.0≤a≤1.2, 0.7≤x<1, 0<y<1, 0≤z<1, 0≤c<1, x+y+z+c=1, and 0≤b≤0.2.

17. An electrolyte for a lithium secondary battery, the electrolyte comprising:

a compound represented by Formula 1;

a lithium salt; and

an organic solvent,

wherein an amount of the compound represented by Formula 1 is about 0.1 weight percent to about 3.0 weight percent, based on a total weight of the electrolyte, and wherein the electrolyte further comprises a disultone compound represented by Formula 7:

wherein, in Formula 1, R 1 to R 15 are each independently hydrogen, fluorine, a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group, or a combination thereof.

wherein when at least one of R 1 to R 15 is hydrogen, at least one of R 1 to R 15 is fluorine, a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group, and

wherein when at least one of R 1 to R 15 is fluorine, at least one of R 1 to R 15 is hydrogen, a substituted or unsubstituted C1-C10 alkyl group, or a substituted or unsubstituted C6-C10 aryl group,

wherein, in Formula 7,

R 1 and R 2 are each independently a substituted C1-C30 alkylene group or an unsubstituted C1-C30 alkylene group, and

a substituent of the substituted C1-C30 alkylene group is at least one of a halogen, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a n-butyl group, a sec-butyl group, a tert-butyl group, a vinyl group, a propinyl group, a butynyl group, a propenyl group, or a butenyl group.

18. The lithium secondary battery of claim 17 , wherein the compound represented by Formula 1 is a compound represented by at least one of Formula 3, Formula 4, Formula 6, or Formula 6b: