ELECTROLYTIC SOLUTION FOR LITHIUM ION SECONDARY BATTERIES, AND LITHIUM ION SECONDARY BATTERY

The present disclosure provides a lithium ion secondary battery excellent in cycle properties which are important for secondary batteries to be installed in vehicles such as electric vehicles, and provides an electrolytic solution that can be used for producing such a lithium ion secondary battery. An electrolytic solution for a lithium ion secondary battery is an electrolytic solution for a lithium ion secondary battery in which an electrolyte is dissolved in a nonaqueous solvent, and contains cyanomethyl formate and vinylene carbonate. The lithium ion secondary battery includes a positive electrode, a negative electrode, a separator, and the electrolytic solution for a lithium ion secondary battery.