Nonaqueous electrolytic solution and nonaqueous electrolyte secondary battery
View Patent ↗A nonaqueous electrolytic solution that can provide a high energy density nonaqueous electrolyte secondary battery having a high capacity, excellent storage characteristics, and excellent cycle characteristics and suppressing the decomposition of an electrolytic solution and the deterioration thereof when used in a high-temperature environment includes an electrolyte, a nonaqueous solvent, and a compound represented by general formula (1): wherein R 1 , R 2 , and R 3 each independently represent a hydrogen atom, a cyano group, or an optionally halogen atom-substituted hydrogen group having 1 to 10 carbon atoms, with the proviso that R 1 and R 2 do not simultaneously represent hydrogen atoms.
1. A nonaqueous electrolyte secondary battery, comprising
a positive electrode having a positive-electrode active material capable of storing and releasing metal ions,
a negative electrode having a negative-electrode active material containing Si and capable of storing and releasing metal ions, and
a nonaqueous electrolytic solution comprising
at least one compound selected from the group consisting of a monofluorophosphate salt and a difluorophosphate salt, and
a compound represented by formula (3) in an amount of from 0.001% to 10% by weight, with respect to a total amount of the nonaqueous electrolytic solution:
NC—(X) n —CN (3)
wherein in the formula (3),
each X is independently CH 2 , CFH, CF 2 , CHR, CFR, CR 2 , C═O, O, S, NH, or NR;
each R in CHR, CFR, CR 2 , and NR is independently an optionally substituted hydrocarbon group comprising from 1 to 5 carbon atoms or a cyano group; and
n is an integer of from 1 to 12.
2. The nonaqueous electrolytic secondary battery according to claim 1 , wherein each X is independently CH 2 , CFH, CF 2 , CHR, CFR, CR 2 , O, S, or NR.
3. The nonaqueous electrolytic secondary battery according to claim 2 , wherein the compound represented by the formula (3) is at least one compound selected from the group consisting of succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, 3,3′-oxydipropionitrile, 3,3′-thiodipropionitrile, 1,2,3-propanetricarbonitrile, and 1,3,5-pentanetricarbonitrile.
4. The nonaqueous electrolytic secondary battery according to claim 1 , wherein n is an integer of from 5 to 12.
5. The nonaqueous electrolytic secondary battery according to claim 4 , wherein the compound represented by the formula (3) is at least one compound selected from the group consisting of pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, 3,3′-oxydipropionitrile, and 1,3,5-pentanetricarbonitrile.
6. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound is a salt of
at least one ion of a metal element in groups 1, 2, and 13 of the periodic table or a quaternary onium ion, and
one or more monofluorophosphate ions and/or one or more difluorophosphate ions.
7. The nonaqueous electrolytic secondary battery according to claim 6 , wherein the at least one compound is at least one of Li 2 PO 3 F, Na 2 PO 3 F, MgPO 3 F, CaPO 3 F, Al 2 (PO 3 F) 2 , Ga 2 (PO 3 F) 3 , LiPO 2 F 2 , NaPO 2 F 2 , Mg(PO 2 F 2 ) 2 , Ca(PO 2 F 2 ) 2 , Al(PO 2 F 2 ) 3 , and Ga(PO 2 F 2 ) 3 .
8. The nonaqueous electrolytic secondary battery according to claim 7 , wherein the at least one compound is at least one of Li 2 PO 3 F, LiPO 2 F 2 , NaPO 2 F 2 and Mg(PO 2 F 2 ) 2 .
9. The nonaqueous electrolytic secondary battery according to claim 6 , wherein the at least one compound is a salt of a quaternary onium ion, and one or more monofluorophosphate ions and/or one or more difluorophosphate ions.
10. The nonaqueous electrolytic secondary battery according to claim 9 , wherein the quaternary onium ion is represented by formula (4):
wherein R 11 to R 14 each independently represent an optionally substituted hydrocarbon group; and Q represents an atom in group 15 of the periodic table.
11. The nonaqueous electrolytic secondary battery according to claim 10 , wherein Q represents a nitrogen atom or a phosphorus atom.
12. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound is present in an amount of from 0.001% to 5% by weight, with respect to the total amount of the nonaqueous electrolytic solution.
13. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound is present in an amount of from 0.01% to 4% by weight, with respect to the total amount of the nonaqueous electrolytic solution.
14. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound is present in an amount of from 0.05% to 4% by weight with respect to the total amount of the nonaqueous electrolytic solution.
15. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound is present in an amount of from 0.1% to 3% by weight, with respect to the total amount of the nonaqueous electrolytic solution.
16. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound comprises the monofluorophosphate.
17. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound comprises the difluorophosphate.
18. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the at least one compound comprises the monofluorophosphate and the difluorosphate.
19. The nonaqueous electrolytic secondary battery according to claim 1 , wherein the negative-electrode active material containing Si is at least one selected from the group consisting of an oxide of Si in which an element ratio of Si to O is from 0.5 to 1.5, a nitrade of Si in which an element ratio of Si to N is from 0.5 to 1.5, and a carbide of Sin in which an element ratio of Si to C is from 0.5 to 1.5.