CYCLIC QUATERNARY AMMONIUM SALT, NONAQUEOUS SOLVENT, NONAQUEOUS ELECTROLYTE, AND POWER STORAGE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an ionic liquid which has at least one of properties such as high ionic conductivity, a small reduction in ionic conductivity at a low temperature, a low melting point, and a low viscosity, and to provide a power storage device having higher initial charge and discharge efficiency than a power storage device containing a conventional ionic liquid.SOLUTION: A cyclic quaternary ammonium salt is liquid at room temperature and contains a quaternary spiro ammonium cation having an asymmetrical structure including two aliphatic rings and one or more substituents bonded to one or both of the two aliphatic rings and an anion corresponding to the quaternary spiro ammonium cation. The power storage device includes a positive electrode, a negative electrode, and a nonaqueous electrolyte, the nonaqueous electrolyte containing the cyclic quaternary ammonium salt as a nonaqueous solvent.