NOVELTY - The secondary battery has a positive electrode active material provided with layered lithium manganese oxides and spinel lithium manganese oxides to exhibit high irreversible capacity when the battery is overcharged at a high voltage. The material is activated at a high voltage of 4.45 V or higher on a positive electric potential basis to provide additional lithium for the utilization of a 3 V region of the spinel lithium manganese oxides. A graphite conductive material, a binder and a filler are provided in a positive electrode mixture.    USE - High-capacity lithium secondary battery for a two-wheeled electricity vehicle e.g. electronic-bike (e-bike) and e-scooter, an electricity commercial vehicle e.g. electricity truck and electric golf cart, a hybrid electric vehicle (HEV) and a plug-in HEV (all claimed). Can also be used for a portable electronic apparatus such as laptop computer, mobile telephone and personal digital assistant (PDA).    ADVANTAGE - The positive electrode active material with the spinel lithium manganese oxides and the layered lithium manganese oxides is charged at the high voltage to prevent low output caused by a sudden voltage drop in a specific state of charge (SOC) region, thus widening the available SOC region and improving safety.    DETAILED DESCRIPTION - The secondary battery is made of one among magnesium, aluminum, nickel, cobalt, iron, chromium, copper, boron, calcium, niobium, molybdenum, strontium, antimony, tungsten, titanium, vanadium, zirconium, zinc or manganese. The lithium manganese oxides are selected from group consisting of lithiated cobalt oxide, lithiated nickel oxide, lithium manganese oxide, lithium-cobalt-nickel oxide, lithium-cobalt-manganese oxide, lithium manganese-nickel oxide or lithium-cobalt-nickel-manganese oxide. An INDEPENDENT CLAIM is also included for a method for manufacturing a high-capacity lithium secondary battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a graphical view illustrating a rechargeable cycle of a high-capacity lithium secondary battery.