Nonaqueous electrolytic solution and energy storage device using same
A nonaqueous electrolytic solution prepared by dissolving an electrolyte salt in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains at least one kind of an isocyanate compound having an ester structure represented by the following general formula (I): (wherein R represents an alkyl group, an alkenyl group, a C 6 to C 12 aryl group, an alkyloxy group, an alkenyloxy group, an isocyanatoalkyloxy group, or an aryloxy group in which at least one of the hydrogen atom may be substituted with a halogen atom. X represents a linear or branched alkylene group in which at least one of the hydrogen atom may be substituted with a halogen atom, or a bivalent linking group comprising at least one ether bond).
1. A nonaqueous electrolytic solution, comprising:
a nonaqueous solvent;
an electrolyte salt dissolved in the nonaqueous solvent; and
from 0.001 to 10 mass % of an isocyanate compound of the formula (I):
wherein R represents a C 1 to C 6 alkyl group optionally substituted with a fluorine atom, a C 2 to C 6 alkenyl group optionally substituted with a fluorine atom, a C 6 to C 12 aryl group optionally substituted with a fluorine atom, a C 1 to C 6 alkyloxy group optionally substituted with a fluorine atom, a C 2 to C 6 alkenyloxy group optionally substituted with a fluorine atom, a C 2 to C 6 isocyanatoalkyloxy group optionally substituted with a fluorine atom, or a C 6 to C 12 aryloxy group optionally substituted with a fluorine atom, and
X represents a C 1 to C 6 linear or branched alkylene group optionally substituted with a fluorine atom, or a C 2 to C 6 bivalent linking group comprising at least one ether bond.
2. The nonaqueous electrolytic solution of claim 1 , wherein R is a C 1 to C 6 alkyl group optionally substituted with a fluorine atom or a C 2 to C 6 alkenyl group optionally substituted with a fluorine atom.
3. The nonaqueous electrolytic solution of claim 2 , wherein R is a C 2 to C 6 alkenyl group or a C 2 to C 6 isocyanatoalkyloxy group.
4. The nonaqueous electrolytic solution of claim 1 , wherein X is a C 1 to C 6 linear or branched alkylene group optionally substituted with a fluorine atom.
5. The nonaqueous electrolytic solution of claim 1 , wherein the isocyanate compound is at least one member selected from the group consisting of 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2-(2-isocyanatoethoxy)ethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2-(2-isocyanatoethoxy)ethyl crotonate, and bis(2-isocyanatoethyl)carbonate.
6. The nonaqueous electrolytic solution of claim 1 , wherein the nonaqueous solvent comprises a cyclic carbonate and a chain ester.
7. The nonaqueous electrolytic solution of claim 6 , wherein the cyclic carbonate is at least one member selected from the group consisting of a cyclic carbonate having an unsaturated bond, a cyclic carbonate having a fluorine atom, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, and 2,3-butylene carbonate.
8. The nonaqueous electrolytic solution of claim 6 , wherein the cyclic carbonate comprises a cyclic carbonate having a unsaturated bond that is a carbon-carbon double bond or a carbon-carbon triple bond and a cyclic carbonate having a fluorine atom.
9. The nonaqueous electrolytic solution of claim 6 , wherein the chain ester is at least one member selected from the group consisting of an asymmetric chain carbonate, a symmetric chain carbonate, and a chain carboxylic acid ester.
10. The nonaqueous electrolytic solution of claim 6 , further comprising:
0.001 to 5 mass % of at least one of a nitrile compound and a sultone compound.
11. An energy storage device, comprising:
a positive electrode;
a negative electrode; and
the nonaqueous electrolytic solution of claim 6 .
12. The nonaqueous electrolytic solution of claim 1 , further comprising:
001 to 5 mass % of at least one of a nitrile compound and a sultone compound.
13. The nonaqueous electrolytic solution of claim 12 , wherein each of the nitrile compound and the sultone compound is included in an amount of from 0.005 to 1 mass %.
14. The nonaqueous electrolytic solution of claim 1 , wherein the electrolytic salt is a lithium salt or an onium salt.
15. An energy storage device, comprising:
a positive electrode;
a negative electrode; and
the nonaqueous electrolytic solution of claim 14 .
16. The nonaqueous electrolytic solution of claim 1 , wherein the electrolytic salt comprises at least one member selected from the group consisting of LiPF 6 , LiPO 2 F 2 , Li 2 PO 3 F, LiBF 4 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiN(SO 2 F) 2 , lithium difluorobis[oxalate-O,O′] phosphate, and lithium tetrafluoro[oxalate-O,O′] phosphate.
17. The nonaqueous electrolytic solution of claim 1 , wherein a concentration of the electrolytic salt is 0.3 to 2.5 M with respect to the nonaqueous solvent.
18. An energy storage device, comprising:
a positive electrode;
a negative electrode; and
the nonaqueous electrolytic solution of claim 1 .
19. The energy storage device of claim 18 , wherein the positive electrode comprises a positive electrode active material comprising at least one member selected from the group consisting of a lithium complex metal oxide and a lithium-containing olivine-type phosphoric acid salt.
20. The energy storage device of claim 18 , wherein the negative electrode comprises a negative electrode active material comprising at least one member selected from the group consisting of lithium metal, a lithium alloy, a carbon material which can absorb and release lithium, and a metal compound which can absorb and release lithium.