NOVELTY - A non-aqueous-electrolyte secondary battery is operated by charging/discharging using site of 4 V discharge region and site of 3 V discharge region. The battery consists of anode (4), cathode (3), and non-aqueous electrolyte. The anode contains an anode compound material consisting of lithium-manganese complex oxide. The cathode contains cathode compound material consisting of powder of carbon material. The cathode consists of a metal lithium foil which adds lithium of amount equivalent to unactivated volume existing in anode compound material.    USE - For operating non-aqueous-electrolyte secondary batteries.    ADVANTAGE - The method improves the energy density and cycle characteristics of non-aqueous-electrolyte secondary batteries, and suppresses reduction in discharge capacitance.    DETAILED DESCRIPTION - A non-aqueous-electrolyte secondary battery is operated by charging/discharging using the site of 4 V discharge region and the site of 3 V discharge region. The battery consists of an anode, a cathode, and a non-aqueous electrolyte. The anode contains an anode compound material consisting of lithium-manganese complex oxide and molded in the shape of a plate or sheet. The cathode contains cathode compound material consisting of powder of carbon material and molded in the shape of a plate or sheet. The cathode consists of a metal lithium foil which adds lithium of amount equivalent to unactivated volume existing in the anode compound material. The lithium-manganese complex oxide is of formula: LiMn2-xMxO4, where M is titanium, vanadium, chromium, iron, cobalt, nickel, aluminum, silver, magnesium and/or lithium, and x is 0-1. The lithium-manganese complex oxide is surface-coated with a conductive polymer.    DESCRIPTION OF DRAWING(S) - The figure shows the sectional drawing of coin-shaped non-aqueous-electrolyte secondary battery. (Drawing includes non-English language text)    Battery case (1)    Sealing board (2)    Cathode (3)    Anode (4)    Separator (6)