Abstract: Provided is a new 5 V-class spinel-type lithium-manganese-containing composite oxide capable of achieving both the expansion of a high potential capacity region and the suppression of gas generation. Proposed is the spinel-type lithium-manganese-containing composite oxide comprising Li, Mn, O and two or more other elements, and having an operating potential of 4.5 V or more at a metal Li reference potential, wherein a peak is present in a range of 14.0 to 16.5° at 2?, in an X-ray diffraction pattern measured by a powder X-ray diffractometer (XRD) using CuK?1 ray.

Abstract: A positive electrode active material comprising a lithium metal composite oxide having a layered crystal structure provides a novel lithium metal composite oxide powder which can suppress the reaction with an electrolytic solution and raise the charge-discharge cycle ability of a battery, and can improve the output characteristics of a battery. A lithium metal composite oxide powder comprises a particle having a surface portion where one or a combination of two or more (“surface element A”) of the group consisting of Al, Ti and Zr is present, on the surface of a particle comprising a lithium metal composite oxide having a layered crystal structure, wherein the amount of surface LiOH is smaller than 0.10% by weight, and the amount of surface Li2CO3 is smaller than 0.25% by weight; in an X-ray diffraction pattern, the ratio of an integral intensity of the (003) plane of the lithium metal composite oxide to that of the (104) plane thereof is higher than 1.

Abstract: The present invention relates to a positive electrode active material including a lithium metal composite oxide having a layer crystal structure, and provides a novel positive electrode active material for a lithium secondary cell, which can suppress the reaction with an electrolyte solution and can raise the charge-discharge cycle ability of the cell, and can make good the output characteristics of the cell.