One object is to provide a power storage device including an electrolyte using a room-temperature ionic liquid which includes a univalent anion and a cyclic quaternary ammonium cation having excellent reduction resistance. Another object is to provide a high-performance power storage device. A room-temperature ionic liquid which includes a cyclic quaternary ammonium cation represented by a general formula (G1) below is used for an electrolyte of a power storage device. In the general formula (G1), one or two of R1 to R5 are any of an alkyl group having 1 to 20 carbon atoms, a methoxy group, a methoxymethyl group, and a methoxyethyl group. The other three or four of R1 to R5 are hydrogen atoms. A− is a univalent imide anion, a univalent methide anion, a perfluoroalkyl sulfonic acid anion, tetrafluoroborate (BF4−), or hexafluorophosphate (PF6−).
一个目标是提供一种使用室温
离子液体的电解质的储能装置,该
离子液体包括一个具有优异还原抗性的一价阴离子和一个环状季
铵阳离子。另一个目标是提供一种高性能的储能装置。使用一个包括通式(G1)所表示的环状季
铵阳离子的室温
离子液体作为储能装置的电解质。在通式(G1)中,R1到R5中的一到两个是具有1到20个碳原子的烷基,一个甲氧基,一个甲氧甲基或一个甲氧乙基。其余的三到四个是氢原子。A-是一价
亚胺阴离子,一价甲基阴离子,
全氟烷基
磺酸阴离子,四
氟硼酸根(
BF4-)或
六氟磷酸根(PF6-)。