| abstract |
A high capacity high safety lithium ion capacitor having high energy density and output density. The lithium ion capacitor has a positive electrode (1) formed of a material which can reversibly dope lithium ions and/or anions, a negative electrode (2) formed of a material which can reversibly doped lithium ions, and aprotic organic solvent solution containing lithium salt as the electrolyte. The positive electrode (1) and the negative electrode (2) are layered or rolled with a separator in between. The positive electrode (1) has an area smaller than that of the negative electrode (2), and the surface of the positive electrode is included in the surface of the negative electrode in the layered or rolled state. |