Nonaqueous electrolyte solution for lithium secondary battery and lithium secondary battery using the same
View Patent ↗The present invention provides (1) a sulfone compounds having a propargyl group, (2) a nonaqueous electrolytic solution for lithium secondary batteries, which comprises an electrolyte salt dissolved in a nonaqueous solvent and contains a sulfone compound having a specific structure that has an SO 2 group with a propargyl group or a vinyl group bonding thereto, in an amount of from 0.01 to 10% by weight of the nonaqueous electrolytic solution, and which can prevent gas generation and is excellent in battery characteristics such as cycle property and the like, and (3) a lithium secondary battery comprising a positive electrode, a negative electrode and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains a sulfone compound having a specific structure, in an amount of from 0.01 to 10% by weight of the nonaqueous electrolytic solution.
1. A nonaqueous electrolytic solution for lithium secondary batteries, comprising an electrolyte salt dissolved in a nonaqueous solvent and containing bis(2-propynyl)sulfone and/or a sulfone compound represented by formula (II) in an amount of from 0.01 to 10% by mass of the nonaqueous electrolytic solution:
wherein R 2 represents a 2-propynyl group or a vinyl group; m is 2 or 3; A represents a divalent linking group having from 1 to 5 carbon atoms and optionally containing an ether bond when m is 2, but when m is 3, A represents a trivalent linking group composed of carbon and hydrogen atoms and having from 3 to 5 carbon atoms.
2. The nonaqueous electrolytic solution according to claim 1 , wherein the nonaqueous solvent comprises a cyclic carbonate and a linear carbonate.
3. The nonaqueous electrolytic solution according to claim 2 , wherein cyclic carbonate is at least one selected from the group consisting of ethylene carbonate, propylene carbonate, vinylene carbonate, 4-fluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolan-2-one, and cis-4,5-difluoro-1,3-dioxolan-2-one.
4. The nonaqueous electrolytic solution according to claim 2 , wherein the linear carbonate comprises a symmetric linear carbonate and an asymmetric linear carbonate.
5. The nonaqueous electrolytic solution according to claim 4 , wherein the symmetric linear carbonate is one or more selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate.
6. The nonaqueous electrolytic solution according to claim 4 , wherein the asymmetric linear carbonate is one or more selected from the group consisting of methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, and ethyl propyl carbonate.
7. The nonaqueous electrolytic solution according to claim 1 , wherein the electrolyte salt is one or more selected from the group consisting of LiPF 6 , LiBF 4 , LiN(SO 2 CF 3 ) 2 , and LiN(SO 2 C 2 F 5 ) 2 .
8. The nonaqueous electrolytic solution according to claim 7 , wherein the electrolyte salt comprises LiPF 6 in a molar ratio LiPF 6 /(LiBF 4 or LiN(SO 2 CF 3 ) 2 or LiN(SO 2 C 2 F 5 ) 2 ) of from 70/30 to 99/1.
9. The nonaqueous electrolytic solution according to claim 1 , wherein m is 2 and A represents a divalent linking group having from 1 to 5 carbon atoms and containing an ether bond.
10. The nonaqueous electrolytic solution according to claim 1 , wherein the sulfone compound represented by formula (II) is one or more selected from the group consisting of bis(2-propynyl)sulfone, 1,2-bis(2-propynylsulfonyl)ethane, 1,3-bis(2-propynylsulfonyl)propane, 2,2′-bis(2-propynylsulfonylethyl)ether, bis(vinylsulfonyl)methane, 1,2-bis(vinylsulfonyl)ethane, 1,4-bis(vinylsulfonyl)butane, bis(2-vinylsulfonylethyl)ether, bis(vinylsulfonylpropyl)ether, and ethylene glycol bis(vinylsulfonylethyl)ether.
11. A lithium secondary battery comprising a positive electrode, a negative electrode and a nonaqueous electrolytic solution of an electrolyte salt dissolved in a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains bis(2-propynyl)sulfone and/or a sulfone compound of formula (II) in an amount of from 0.01 to 10% by mass of the nonaqueous electrolytic solution:
wherein R 2 represents a 2-propynyl group or a vinyl group, m is 2 or 3, and A represents a divalent linking group having from 1 to 5 carbon atoms and optionally containing an ether bond when m is 2, but when m is 3, A represents a trivalent linking group composed of carbon and hydrogen atoms and having from 3 to 5 carbon atoms.
12. The lithium secondary battery according to claim 11 , wherein the positive electrode comprises a positive electrode active material comprising one or more selected from the group consisting of a lithium complex metal oxide and a lithium-containing olivine phosphate.
13. The lithium secondary battery according to claim 11 , wherein the negative electrode comprises a negative electrode active material comprising one or more selected from the group consisting of lithium metal, a lithium alloy, a high-crystalline carbon material capable of absorbing and releasing lithium, and a metal compound capable of absorbing and releasing lithium.