Nonaqueous electrolyte and lithium secondary battery employing the same
View Patent ↗A nonaqueous electrolyte which contains a nonaqueous organic solvent and a lithium salt dissolved therein is provided. Also provided is a lithium secondary battery employing the nonaqueous electrolyte.
1. A nonaqueous electrolyte which comprises a nonaqueous organic solvent and a lithium salt dissolved therein, wherein the nonaqueous organic solvent comprises a sulfonic compound represented by formula (1):
wherein L 1 represents a Z 1 -valent connecting group composed of carbon atom(s) and hydrogen atoms, R 1 represents a hydrocarbon group, and Z 1 is 3 or 4.
2. The nonaqueous electrolyte according to claim 1 , wherein said nonaqueous organic solvent comprises at least one compound selected from the group consisting of an acid anhydride and a carbonic ester having an unsaturated bond.
3. The nonaqueous electrolyte according to claim 1 , wherein the total content of the sulfonic compound represented by formula (1) is 0.01 to 15% by weight based on the nonaqueous electrolyte.
4. The nonaqueous electrolyte according to claim 1 wherein L 1 represents a trivalent or a tetravalent connecting group.
5. The nonaqueous electrolyte according to claim 1 wherein when Z 1 is 3 the L 1 represents
and R 1 represents an alkyl group of 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an aryl group having 6 to 9 carbon atoms, or an aralkyl group having 7 to 8 carbon atoms.
6. The nonaqueous electrolyte according to claim 5 , wherein R 1 represents an alkyl group having 1 to 2 carbon atoms.
7. The nonaqueous electrolyte according to claim 6 , wherein the alkyl group is methyl or ethyl.
8. The nonaqueous electrolyte according to claim 7 , wherein the alkyl group is methyl.
9. The nonaqueous electrolyte according to claim 5 , wherein R 1 represents an aryl group having 6 to 9 carbon atoms.
10. The nonaqueous electrolyte according to claim 9 , wherein the aryl group is selected from the group consisting of phenyl, tolyl, ethyl phenyl, dimethylphenyl and trimethyl phenyl.
11. The nonaqueous electrolyte according to claim 10 , wherein the aryl group is tolyl.
12. The nonaqueous electrolyte according to claim 1 wherein when Z 1 is 4 the L 1 represents
and R 1 represents an alkyl group of 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an aryl group having 6 to 9 carbon atoms, or an aralkyl group having 7 to 8 carbon atoms.
13. The nonaqueous electrolyte according to claim 12 , wherein R 1 represents an alkyl group having 1 to 2 carbon atoms.
14. The nonaqueous electrolyte according to claim 13 , wherein the alkyl group is methyl or ethyl.
15. The nonaqueous electrolyte according to claim 14 , wherein the alkyl group is methyl.
16. The nonaqueous electrolyte according to claim 12 , wherein R 1 represents an aryl group having 6 to 9 carbon atoms.
17. The nonaqueous electrolyte according to claim 16 , wherein the aryl group is selected from the group consisting of phenyl, tolyl, ethyl phenyl, dimethylphenyl and trimethyl phenyl.
18. The nonaqueous electrolyte according to claim 17 , wherein the aryl group is tolyl.
19. A lithium secondary battery employing the nonaqueous electrolyte according to claim 1 .