Abstract: A mass-producible lithium ion capacitor that allows lithium ions to be easily occluded by a negative electrode in advance is provided. A layered member includes: two copper foils each having a portion in which tabs are formed on one side along the longitudinal direction of the copper foils, and a portion in which a large number of through holes are formed and which is disposed adjacent to the portion with the tabs, and lithium metal having a thin plate shape and sandwiched between the copper foils to contact the portions with the through holes of the copper foils. The tabs are joined to a negative current collector ring, and electrically connected to a negative current collecting member. By leaving the layered member to stand for a predetermined period, it is possible to cause lithium ions to be occluded by a negative active material of the lithium ion capacitor.

Abstract: A non-aqueous secondary battery having a long life-time and a high capacity density is provided by increasing the discharging capacity of the negative electrode and extending the life-time of the negative electrode. The nonaqueous secondary battery has a positive electrode and a negative electrode reversibly absorbing and discharging an alkaline metal and a nonaqueous electrolyte, wherein the negative electrode is made of an inter-metallic compound containing at least one element selected from the group consisting of 4A group elements, P and Sb, the inter-metallic compound has any one of CaF.sub.2 type, ZnS type and AlLiSi type crystal structures, and the CaF.sub.2 type structure is any one an inverse-fluorite structure and a fluorite structure having a lattice constant larger than 6.36 .ANG..