| abstract |
Disclosed is a lithium ion capacitor comprising a positive electrode composed of a substance which can reversibly support lithium ions and/or anions, a negative electrode composed of a substance which can reversibly support lithium ions, and an electrolyte solution composed of a lithium salt in an aprotic organic solvent. (a) The negative electrode active material is a hardly-graphitizable carbon wherein the hydrogen/carbon atomic number ratio is not less than 0 but less than 0.05. (b) The negative electrode and/or the positive electrode is doped with lithium ions in advance so that the negative electrode potential after being discharged to 1/2 of the charging voltage of the cell is not more than 0.15 V with respect to the lithium metal potential. |