ALKALI METAL ION CAPACITOR, METHOD FOR PRODUCING THE SAME AND METHOD FOR CHARGING AND DISCHARGING THE SAME

摘要

An alkali metal ion capacitor includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The electrolyte contains an alkali metal salt and an ionic liquid. The alkali metal salt is a salt of a first alkali metal ion serving as a first cation and a first anion. The negative electrode active material is pre-doped with a second alkali metal ion until the potential of the negative electrode reaches 0.05 V or less with respect to a second alkali metal. The alkali metal ion capacitor has an upper-limit voltage for charging and discharging of more than 3.8 V.

主权项

1. An alkali metal ion capacitor comprising a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator disposed between the positive electrode and the negative electrode, and an electrolyte,
wherein the electrolyte contains an alkali metal salt and an ionic liquid, a total content of the alkali metal salt and the ionic liquid in the electrolyte is 60 mass % or more, and the electrolyte has alkali metal ion conductivity, the alkali metal salt is a salt of a first alkali metal ion serving as a first cation and a first anion, the positive electrode active material contains a material that reversibly carries at least the first anion, the negative electrode active material contains a material that reversibly carries the first alkali metal ion, the negative electrode active material is pre-doped with a second alkali metal ion until a potential of the negative electrode reaches 0.05 V or less with respect to a second alkali metal, and the alkali metal ion capacitor has an upper-limit voltage for charging and discharging of more than 3.8 V.