Predoping material for electrical lithium or sodium storage device

There are provided a predoping material, an electric storage device including the material, and a method of producing the device. The predoping material is used for an alkali metal ion electric storage device and is represented by Formula (1): €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ R(5SM)n€ƒ€ƒ€ƒ€ƒ€ƒ(I) where M represents lithium or sodium; n represents an integer of 2 to 6; and R represents an aliphatic hydrocarbon, optionally substituted aromatic hydrocarbon, or optionally substituted heterocycle having 1 to 10 carbon atoms.