Abstract: A lithium secondary battery is produced by employing a charging method where a positive electrode upon charging has a maximum achieved potential of 4.3 V (vs. Li/Li+) or lower. The lithium secondary battery contains an active material including a solid solution of a lithium transition metal composite oxide having an ?-NaFeO2-type crystal structure. The solid solution has a diffraction peak observed near 20 to 30° in X-ray diffractometry using CuK? radiation for a monoclinic Li[Li1/3Mn2/3]O2-type before charge-discharge. The lithium secondary battery is charged to reach at least a region with substantially flat fluctuation of potential appearing in a positive electrode potential region exceeding 4.3 V (vs. Li/Li+) and 4.8 V (vs. Li/Li+) or lower. A dischargeable electric quantity in a potential region of 4.3 V (vs. Li/Li+) or lower is 177 mAh/g or higher.

Abstract: The active material for a lithium secondary battery includes a solid solution of a lithium transition metal composite oxide having an ?-NaFeO2 type crystal structure, in which the composition ratio of Li, Co, Ni, and Mn contained in the solid solution satisfies Li1+(1/3)xCo1?x?yNi(1/2)yMn(2/3)x+(1/2)y (x+y?1, 0?y and 1?x?y=z); in an Li[Li1/3Mn2/3]O2(x)-LiNi1/2Mn1/2O2(y)-LiCoO2(z) type ternary phase diagram, (x, y, z) is represented by values in a range present on or within a line of a heptagon (ABCDEFG) defined by the vertexes; point A(0.45, 0.55, 0), point B(0.63, 0.37, 0), point C(0.7, 0.25, 0.05), point D(0.67, 0.18, 0.15), point E(0.75, 0, 0.25), point F(0.55, 0, 0.45), and point G(0.45, 0.2, 0.35); and the intensity ratio between the diffraction peaks on (003) plane and (104) plane measured by X-ray diffractometry before charge-discharge is I(003)/I(104)?1.56 and at the end of discharge is I(003)/I(104)>1.

Abstract: A process for producing a lithium secondary battery employs a charging method where a positive electrode upon charging has a maximum achieved potential of 4.3 V (vs. Li/Li+) or lower. The process includes charging the lithium secondary battery to reach at least a region with relatively flat fluctuation of potential appearing in a positive electrode potential region exceeding 4.3 V (vs. Li/Li+) and 4.8V (vs. Li/Li+) or lower. The lithium secondary battery includes an active material having a solid solution of a lithium transition metal composite oxide having an ?-NaFeO2 type crystal structure. The composition ratio of Li, Co, Ni, and Mn contained in the solid solution satisfies Li1+1/3xCo1?x?yNiy/2Mn2x/3+y/2(x+y?1, 0?y and 1?x?y=z).

Abstract: A process for producing a lithium secondary battery employs a charging method where a positive electrode upon charging has a maximum achieved potential of 4.3 V (vs. Li/Li+) or lower. The process includes charging the lithium secondary battery to reach at least a region with relatively flat fluctuation of potential appearing in a positive electrode potential region exceeding 4.3 V (vs. Li/Li+) and 4.8V (vs. Li/Li+) or lower. The lithium secondary battery includes an active material having a solid solution of a lithium transition metal composite oxide having an ?-NaFeO2 type crystal structure. The composition ratio of Li, Co, Ni, and Mn contained in the solid solution satisfies Li1?1/3xCo1?x?yNiy/2Mn2x/3+y/2(x+y?1, 0?y and 1?x?y=z).

Abstract: The present invention provides an active material for a lithium secondary battery with a high discharge capacity, particularly for a lithium secondary battery that can increase the discharge capacity in a potential region of 4.3 V or lower, a method for producing the same, a lithium secondary battery having a high discharge capacity, and a method for producing the same. The active material for a lithium secondary battery includes a solid solution of a lithium transition metal composite oxide having an ?-NaFeO2 type crystal structure, in which the composition ratio of Li, Co, Ni, and Mn contained in the solid solution satisfies Li1+(1/3)xCo1?x?yNi(1/2)yMn(2/3)x+(1/2)y (x+y?1, 0?y and 1?x?y=z); in an Li[Li1/3Mn2/3]O2(x)-LiNi1/2Mn1/2O2(y)-LiCoO2(z) type ternary phase diagram, (x, y, z) is represented by values in a range present on or within a line of a heptagon (ABCDEFG) defined by the vertexes; point A(0.45, 0.55, 0), point B(0.63, 0.37, 0), point C(0.7, 0.25, 0.05), point D(0.67, 0.18, 0.15), point E(0.

Abstract: The present invention is concerned on the manufacturing process of Li-contained nickel oxyhydroxide obtained by a lithium absorption process with contact reaction between nickel oxyhydroxide and a solution obtained by dissolving metallic Li and polycyclic aromatic compounds in a solvent. Moreover, the nonaqueous electrolyte electrochemical cell using Li-contained nickel oxyhydroxide active material obtained by this manufacturing process is able to be high performance with a low manufacturing price by its simple process compared to the existing process by electrochemical process and so on.