Lithium secondary battery

A lithium ion secondary battery comprising:

• a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte,
• wherein the electrolyte contains a compound represented by formula (4):
• wherein Z1 and Z2 each represent any one of an allyl group, a methallyl group, a vinyl group, an acryl group, and a methacryl group;
• wherein the electrolyte further comprises:
• a cyclic carbonate compound represented by formula (1):
• wherein R1, R2, R3 and R4 each represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms and a fluorinated alkyl group having 1 to 3 carbon atoms,
• a compound represented by formula (3):
• wherein R7 and R8 each represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms and a fluorinated alkyl group having 1 to 3 carbon atoms;
• wherein the electrolyte further comprises a linear carbonate represented by formula (2):
• wherein R5 and R6 each represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms, and a fluorinated alkyl group having 1 to 3 carbon atoms;
• and
• wherein the compound represented by formula (1) is ethylene carbonate,
• the compound represented by formula (2) is at least one of ethyl methyl carbonate and dimethyl carbonate,
• the compound represented by formula (3) is vinylene carbonate, and
• the compound represented by formula (4) is dimethacryl carbonate.

A lithium ion secondary battery comprising:

• a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte,
• wherein the electrolyte contains a compound represented by formula (4):
• wherein Z1 and Z2 each represent any one of an allyl group, a methallyl group, a vinyl group, an acryl group, and a methacryl group;
• wherein the electrolyte further comprises:
• a cyclic carbonate compound represented by formula (1):
• wherein R1, R2, R3, and R4 each represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms and a fluorinated alkyl group having 1 to 3 carbon atoms,
• a compound represented by formula (3):
• wherein R7 and R8 each represent any one of hydrogen, fluorine, chlorine, an alkyl group having 1 to 3 carbon atoms and a fluorinated alkyl group having 1 to 3 carbon atoms;
• and
• wherein compound represented by formula (4) is dimethacryl carbonate.