Electrolyte additive
The electrolyte additive includes a neutral compound represented by formula (1) and having, in the molecule, a trialkyl silyl group. It can improve the withstand voltage of the electrolyte and be applied to electrolyte for lithium-ion rechargeable batteries. In formula (1), R 1 each represent independent C1-8 alkyl groups, R 2 each represent independent C1-8 alkyl groups, A represents a C1-10 alkylene group, X represents either a single bond, a methylene group or one of the linking groups represented by formulas (2) to (4), m represents an integer from 1 to 3, n represents an integer from 0 to 2, where m+n is 2 if X is a single bond, a methylene group, a linking group represented by formula (2) or a linking group represented by formula (3), and m+n is 3 if X is a linking group represented by formula (4). In formula (3), R 3 represents a C1-8 alkyl group.
1. An electrolyte additive comprising a neutral compound of formula (1) which has a trialkylsilyl group in the molecule:
wherein R 1 s each independently represent an alkyl group having 1 to 8 carbon atoms, A represents an alkylene group having 1 to 10 carbon atoms, X represents one selected from any one of linking groups of the following formulae (2) to (4), m represents an integer of 2 to 3, where m is 2 when X is a linking group of the following formula (2) or a linking group of the following formula (3), and m is 3 when X is a linking group of the following formula (4):
wherein R 3 in formula (3) represents an alkyl group having 1 to 8 carbon atoms.
2. The electrolyte additive according to claim 1 , wherein said R 1 s each independently represent an alkyl group having 1 to 4 carbon atoms, said X represents one selected from any one of linking groups of the formulae (2) and (3), m is 2.
3. The electrolyte additive according to claim 1 , wherein each of all R 1 s is a methyl group.
4. The electrolyte additive according to claim 1 , wherein A is an alkylene group having 2 to 5 carbon atoms.
5. The electrolyte additive according to claim 1 , comprising any of compounds of the following formulae (1B) and (1D):
wherein Me represents a methyl group.
6. The electrolyte additive according to claim 1 , which is a voltage resistance improving agent for an electrolytic solution.
7. The electrolyte additive according to claim 1 , which is a solvent for an electrolytic solution.
8. An electrolytic solution comprising the electrolyte additive according to claim 1 , an organic solvent and an electrolyte salt.
9. The electrolytic solution according to claim 8 , wherein the organic solvent contains a carbonate.
10. The electrolytic solution according to claim 9 , wherein the organic solvent contains two or more carbonates.
11. An electrolytic solution which contains the electrolyte additive according to claim 1 and an electrolyte salt and is free of an organic solvent.
12. A power storage device formed using the electrolytic solution according to claim 8 .
13. A power storage device formed using the electrolyte additive according to claim 1 .
14. The power storage device according to claim 12 , which is a secondary battery or an electric double-layer capacitor.
15. A method comprising adding the electrolyte additive according to claim 1 to electrolytic solution containing a solvent and an electrolyte salt to improve the voltage resistance of the electrolytic solution.
16. A compound of the following formula (1B):
wherein Me represents a methyl group.
17. A compound of the following formula (1D),
wherein Me represents a methyl group.