Abstract: A positive electrode active material for a lithium secondary battery containing a lithium-cobalt composite oxide, which has a large volume capacity density, has a high safety and is excellent in charge and discharge cyclic durability, and its production process, are provided. A lithium-cobalt composite oxide represented by the formula LipCoxMyOzFa (wherein M is a transition metal element other than Co or an alkaline earth metal element, 0.9?p?1.1, 0.980?x?1.000, 0?y?0.02, 1.9?z?2.1, x+y=1 and 0?a?0.

Abstract: A composite oxide suitable for an active material of a positive electrode for a lithium secondary cell which can be used in a wide range of voltage, has a large electric capacity and excellent low temperature performance and is excellent in the durability for charge-discharge cycles and highly safe, a process for its production, and a positive electrode and a cell employing it, are presented. The composite oxide is a lithium-cobalt composite oxide which is represented by the formula LiCo1-xMxO2, (wherein 0?x?0.02 and M is at least one member selected from the group consisting of Ta, Ti, Nb, Zr and Hf), and which has a half-width of the diffraction peak for (110) face at 2?=66.5±1°, of from 0.070 to 0.180°, as measured by the X-ray diffraction using CuK? as a ray source.

Abstract: A composite oxide suitable for an active material of a positive electrode for a lithium secondary cell which can be used in a wide range of voltage, has a large electric capacity and excellent low temperature performance and is excellent in the durability for charge-discharge cycles and highly safe, a process for its production, and a positive electrode and a cell employing it, are presented. The composite oxide is a lithium-cobalt composite oxide which is represented by the formula LiCo1-xMxO2, (wherein 0?x?0.02 and M is at least one member selected from the group consisting of Ta, Ti, Nb, Zr and Hf), and which has a half-width of the diffraction peak for (110) face at 2?=66.5±1°, of from 0.070 to 0.180°, as measured by the X-ray diffraction using CuK? as a ray source.

Abstract: A composite oxide suitable for an active material of a positive electrode for a lithium secondary cell which can be used in a wide range of voltage, has a large electric capacity and excellent low temperature performance and is excellent in the durability for charge-discharge cycles and highly safe, a process for its production, and a positive electrode and a cell employing it, are presented.