| abstract |
A positive electrode comprising a positive electrode active material, a negative electrode including a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, wherein the electrolyte comprises an alkali metal salt and an ionic liquid, Wherein the sum of the content of the ionic liquid is 60% by mass or more and the alkali metal ion conductivity is the alkali metal salt, and the alkali metal salt is a salt of the first alkali metal ion and the first anion being the first cation, Wherein the negative electrode active material includes a material that reversibly supports the first alkali metal ion, and the negative electrode active material has a potential of not more than 0.05 V with respect to the second alkali metal The second alkali metal ion is pre-doped, and the upper limit of charge-discharge exceeding 3.8 V An alkaline metal ion capacitor having a voltage. |