Abstract: A positive electrode active material included in this non-aqueous electrolyte secondary battery positive electrode includes a lithium-transition metal composite oxide. The lithium-transition metal composite oxide contains 80-95 mol % of Ni and 0-20 mol % of Mn, and 3-8 mol % of a metal element other than Li is present in a Li layer of the lithium-transition metal composite oxide. The ratio m/n of the half width m of the diffraction peak for the (003) plane to the half width n of the diffraction peak for the (110) plane in an x-ray diffraction pattern obtained by x-ray diffraction of the positive electrode active material satisfies 0.72?m/n?0.85. The lithium-transition metal composite oxide is formed from secondary particles that are aggregates of primary particles, the internal porosity of the secondary particles being 1%-5%.

Abstract: A positive-electrode active material for nonaqueous-electrolyte secondary batteries which comprises a given lithium-transition metal composite oxide haying a lamellar structure and a compound A containing Ca and/or Sr, the compound A being present on the surface of or at the boundaries of primary particles of the lithium-transition metal composite oxide. The lamellar structure includes an Li layer where Li reversibly goes in and out, and the proportion of non-lithium metallic element(s) present in the Li layer is 0.7-3.0 mol % with respect to the total amount of the non-lithium metallic elements contained in the lithium-transition metal composite oxide. In analysis by X-ray diffraction, the positive-electrode active material gives an X-ray diffraction pattern in which the ratio of the half-band width in of a diffraction peak for the (003) plane to the half-band width n of a diffraction peak for the (104) plane, m/n, is 0.7.5?m/n?1.0.

Abstract: In this non-aqueous electrolyte secondary battery: a positive electrode active material contains a lithium transition metal oxide that has a layered structure including a Li layer and that contains at least prescribed amounts of Ni, Ca, and Al; the proportion of metal elements, excluding Li, in the Li layer is 0.6-2.0 mol % with respect to the total number of moles of metal elements, excluding Li, contained in the lithium transition total oxide; a negative electrode active material has a coating containing Ca on the surface thereof; and the contained amount of Ca in the coating is not less than 15 mass ppm but less than 80 mass ppm with respect to the total mass of the positive electrode material.

Abstract: A positive electrode active material for a non-aqueous electrolyte secondary battery, according to an example of this embodiment, includes a lithium transition metal composite oxide which has a layered structure and contains at least Ni, Al, and Ca. The lithium transition metal composite oxide has a Ni content of 85-95 mol %, an Al content of at most 8 mol %, and a Ca content of at most 2 mol % with respect to the total amount of metal elements other than Li. In addition, the proportion of metal elements other than Li present in a Li layer is 0.6-2.0 mol % with respect to the total amount of metal elements other than Li contained in the composite oxide.

Abstract: A positive electrode active material for a non-aqueous electrolyte secondary battery contains a lithium-nickel-manganese-containing composite oxide which is represented by composition formula LixNiyMnzMe1-y-zO2 (where Me is a metal element other than Li, Ni, and Mn, x?1.16, 0.3?y?0.7, and 0.3?z?0.7), has a layered structure belonging to space group R-3m, and has a diffraction peak at 2? in the range of greater than or equal to 65° and less than or equal to 67° in an X-ray diffraction pattern when charging and discharging are performed until the charge voltage reaches 4.8 V.