Non-aqueous electrolyte solution and electricity storage device in which same is used

Abstract

Provided are a nonaqueous electrolytic solution having an electrolyte salt dissolved in a nonaqueous solvent, the electrolyte salt including at least one first lithium salt selected from LiPF, LiBF, LiN(SOF), LiN(SOCF), and LiN(SOCF), and at least one second lithium salt selected from a lithium salt having an oxalate structure, a lithium salt having a phosphate structure, and a lithium salt having an S═O group, with a sum total of the first lithium salt and the second lithium salt being four or more, and an energy storage device using the same. This nonaqueous electrolytic solution is not only able to improve electrochemical characteristics at a high temperature and much more improve a discharge capacity retention rate and low-temperature output characteristics after a high-temperature storage test but also able to improve low-temperature input characteristics even for high-density electrodes.