Patent ID: 7629085

Claim:
A nonaqueous electrolytic solution for a lithium secondary battery, comprising an electrolytic salt dissolved in a nonaqueous solvent, which contains 0.01 to 10 wt. % of a sulfur-containing acid ester and 0.01 to 10 wt. % of a triple bond-containing compound, said sulfur-containing acid ester being selected from the group consisting of 1,3-propane sultone, 1,3-butane sultone, glycol sulfite, propylene sulfite, glycol sulfate, propylene sulfate, 1,3-propanediol dimethanesulfonate and 1,4-butanediol dimethanesulfonate, and said triple bond-containing compound being represented by one of the following formulas (I) to (VI): in which R 1 is an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or an aryl group; R 2 is an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group or hydrogen; p is an integer of 1 or 2; each of R 3 to R 19 is independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group or hydrogen, provided that each set of R 4 and R 5 , R 6 and R 7 , R 8 and R 9 , R 10 and R 11 , R 12 and R 13 , R 15 and R 16 , and R 17 and R 18 may combine with each other to form a cycloalkyl group having 3 to 6 carbon atoms; Y 1 is —COOR 20 , —COR 20 or —SO 2 R 20 ; Y 2 is —COOR 21 , —COR 21 or —SO 2 R 21 ; Y 3 is —COOR 22 , —COR 22 or —SO 2 R 22 ; Y 4 is —COOR 23 , —COR 23 or —SO 2 R 23 ; Y 5 is —COOR 24 , —COR 24 or —SO 2 R 24 ; each of R 20 , R 21 , R 22 , R 23 and R 24 is independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms or an aryl group; each of R 25 , R 26 and R 27 is independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms or hydrogen, provided that R 26 and R 27 may combine with each other to form a cycloalkyl group having 3 to 6 carbon atoms; W is sulfoxide, sulfone or oxalyl; Y 6 is an alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or an aralkyl group having 7 to 12 carbon atoms; and x is an integer of 1 or 2.