Lithium salt compound, nonaqueous electrolyte solution using same, lithium ion secondary battery and lithium ion capacitor

摘要

The present invention is concerned with (1) a lithium salt compound including a lithium cation including, as a ligand, at least one ether compound selected from 2,5,8,11-tetraoxadodecane and 2,5,8,11,14-pentaoxapentadecane and a difluorophosphate anion; (2) a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution containing the aforementioned lithium salt compound; (3) a lithium ion secondary battery including a positive electrode, a negative electrode, and the aforementioned nonaqueous electrolytic solution; (4) a lithium ion capacitor using the aforementioned nonaqueous electrolytic solution; and (5) a production method of the aforementioned lithium salt compound, including bringing the aforementioned ether compound and lithium difluorophosphate into contact with each other. The nonaqueous electrolytic solution of the present invention is excellent in high-temperature cyclic property and output characteristics after high-temperature cycles and is capable of suppressing metal elution from a positive electrode or the like.