Abstract: A non-aqueous electrolyte secondary battery having a high capacity and a long life is provided by eliminating or reducing the structural change of a positive electrode active material at high voltages. The non-aqueous electrolyte secondary battery includes a positive electrode having a positive electrode active material that intercalates and deintercalates lithium ions, a negative electrode having a negative electrode active material that intercalates and deintercalates lithium ions, and a non-aqueous electrolyte. The positive electrode active material includes a lithium-cobalt composite oxide containing nickel, manganese, aluminum, and germanium. The percentage of cobalt in the lithium-cobalt composite oxide is 80 mol % or more with respect the total molar amount of metal elements except lithium.

Abstract: Provided is a nonaqueous electrolyte secondary battery in which the structural change of a positive electrode active material is suppressed at high voltage and which can achieve high capacity and long life. The nonaqueous electrolyte secondary battery includes a positive electrode containing a positive electrode active material storing and releasing lithium ions, a negative electrode containing a negative electrode active material storing and releasing lithium ions, and a nonaqueous electrolyte. The positive electrode active material is a cobalt composite oxide which has a layered rock salt structure and which includes a lithium layer containing magnesium, magnesium is present in the lithium layer after charge is performed at a potential of 4.53 V or more versus lithium, and 4.5 mole percent to 10 mole percent of a magnesium-containing compound is present on the negative electrode with respect to magnesium in the positive electrode.

Abstract: A high-capacity nonaqueous electrolyte secondary battery having good load characteristics is provided. The nonaqueous electrolyte secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode, and a nonaqueous electrolyte. The positive electrode contains the active material composed of a lithium transition metal oxide and a positive electrode additive composed of an oxide that contains Li and at least two elements other than Li and oxygen and has an antifluorite structure. The nonaqueous electrolyte secondary battery obtained is charged until the potential of the positive electrode is 4.0 V or higher and 4.65 V or lower (vs. Li/Li+).

Abstract: Provided is a nonaqueous electrolyte secondary battery which is capable of achieving high capacity and long life by suppressing the structural change of a positive electrode active material at high voltage. The nonaqueous electrolyte secondary battery includes a positive electrode containing a positive electrode active material storing and releasing lithium ions, a negative electrode containing a negative electrode active material storing and releasing lithium ions, and a nonaqueous electrolyte. The positive electrode active material is a lithium-cobalt composite oxide containing nickel, manganese, and aluminium and has a rare-earth compound or oxide deposited to a portion of the surface thereof.

Abstract: A nonaqueous electrolyte secondary battery that has high capacity and good load properties. A nonaqueous electrolyte secondary battery includes a positive electrode for a nonaqueous electrolyte secondary battery, a negative electrode, a separator interposed between the positive electrode for a nonaqueous electrolyte secondary battery and the negative electrode, and an electrolyte. The positive electrode for a nonaqueous electrolyte secondary battery includes a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector, the positive electrode active material layer containing a positive electrode active material and a positive electrode additive. The positive electrode additive contains a Li-containing compound that generates gas at 4.2 V (vs. Li/Li+) or less during first charging of the nonaqueous electrolyte secondary battery.

Abstract: A nonaqueous electrolyte secondary battery which can suppress the change in structure of a positive electrode active material at a high voltage is provided. The nonaqueous electrolyte secondary battery has a positive electrode including a positive electrode active material which absorbs and releases lithium ions; a negative electrode including a negative electrode active material which absorbs and releases lithium ions; and a nonaqueous electrolyte. The positive electrode active material has a surface to which a rare earth compound is adhered and includes a lithium cobalt composite oxide containing at least one type selected from the group consisting of Ni, Mn, Ca, Cu, Zn, Sr, Ge, Sn, Si, P, Nb, Mo, S, and W, and charge is performed so that the potential of the positive electrode is 4.53 V or more with reference to lithium.

Abstract: A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material containing a lithium-containing oxide active material, a negative electrode, and a non-aqueous electrolyte. The lithium-containing oxide active material is represented by the general formula LiaMgbMO2±? where 0.65?a?1.05, 0<b?0.3, 0???0.3, and M is at least one of manganese and cobalt.

Abstract: A non-aqueous electrolyte battery has a working electrode 1 having a positive electrode active material, a counter electrode 2, and a non-aqueous electrolyte containing lithium. The positive electrode active material includes a lithium pre-doped transition metal oxide prepared by pre-doping lithium into a sodium-containing transition metal oxide having an initial charge-discharge efficiency of higher than 100% as determined by charging and discharging using a lithium metal negative electrode as a counter electrode, and the sodium-containing transition metal oxide is represented by the compositional formula NaaLibMO2±?, where 0.5?a<1.0, 0<b?0.5, 0?a?0.1, and M is at least one element selected from the group consisting of Ni, Co, and Mn.

Abstract: A method of manufacturing a non-aqueous electrolyte secondary battery by subjecting a sodium-magnesium-containing oxide represented by the general formula NacMgbMO2±a, where 0.65?c?0.75, 0<b?0.3, 0?a?03, and M is at least one of manganese and cobalt, to ion-exchange of sodium for lithium by using a molten salt, an aqueous solution, or an organic solvent, to prepare a positive electrode active material.

Abstract: A method of detecting a condition of a secondary battery is provided. The method includes the steps of: measuring an entropy change at a predetermined state of charge of the secondary battery; charging the secondary battery after the step of measuring an entropy change; repeating the steps of measuring an entropy change and charging the secondary battery; and detecting a deterioration condition of the secondary battery based on the slope of a measured entropy change curve with respect to state of charge.

Abstract: A method for evaluating a secondary battery includes repeatedly performing: an open circuit voltage measurement step of measuring the open circuit voltage of the secondary battery to be evaluated at each of a plurality of temperatures; a potential change measurement step of measuring, after the open circuit voltage measurement step, the potential change in the secondary battery while changing the state of charge of the secondary battery; and an equilibrium potential measurement step of measuring the equilibrium potential of the secondary battery after the potential change measurement step. An entropy variation in each of the different states of charge is calculated based on the open circuit voltages at the plurality of temperatures measured in the state of charge, and a chemical diffusion coefficient in each of the different states of charge is calculated based on the equilibrium potential of the secondary battery and the potential change in the secondary battery both measured in the state of charge.

Abstract: A non-aqueous electrolyte battery has a working electrode 1 having a positive electrode active material, a counter electrode 2, and a non-aqueous electrolyte containing lithium. The positive electrode active material includes a lithium pre-doped transition metal oxide prepared by pre-doping lithium into a sodium-containing transition metal oxide having an initial charge-discharge efficiency of higher than 100% as determined by charging and discharging using a lithium metal negative electrode as a counter electrode, and the sodium-containing transition metal oxide is represented by the compositional formula NaaLibMO2±?, where 0.5?a<1.0, 0<b?0.5, 0???0.1, and M is at least one element selected from the group consisting of Ni, Co, and Mn.

Abstract: A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material containing a lithium-containing oxide active material, a negative electrode, and a non-aqueous electrolyte. The lithium-containing oxide active material is represented by the general formula LiaMgbMO2±?, where 0.65?a?1.05, 0<b?0.3, 0 ???0.3, and M is at least one of manganese and cobalt.