Abstract: A positive electrode active material for a lithium secondary battery, comprising a lithium-containing composite metal oxide in the form of secondary particles formed by aggregation of primary particles capable of being doped and undoped with lithium ions, each of the secondary particles having on its surface a coating layer, the positive electrode active material satisfying the following requirements (1) to (3): (1) the metal oxide has an ?-NaFeO2 type crystal structure of following formula (A): Lia(NibCocM11-b-c)O2??(A) wherein 0.9?a?1.2, 0.9?b<1, 0<c?0.1, 0.9<b+c?1, and M1 represents at least one optional metal selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In and Sn; (2) the coating layer comprises Li and M2, wherein M2 represents at least one optional metal selected from Al, Ti, Zr and W; and (3) the active material has an average secondary particle diameter of 2 to 20 ?m, a BET specific surface area of 0.1 to 2.

Abstract: A lithium-manganese composite oxide containing a lithium-iron-manganese composite oxide represented by the composition formula. Li1+x?w(FeyNizMn1?y?z)1?xO2??, where 0<x<?, 0?w<0.8, 0<y<1, 0<z<0.5, y+z<1, and 0??<0.5, in which at least in a state of charge of a lithium ion battery using the lithium-manganese composite oxide as a positive-electrode active material, at least some of iron atoms are pentavalent.

Abstract: A lithium-manganese composite oxide containing a lithium-iron-manganese composite oxide represented by the composition formula. Li1+x?w(FeyNizMn1?y?z)1?xO2??, where 0<x<1/3, 0?w<0.8, 0<y<1, 0<z<0.5, y+z<1, and 0??<0.5, in which at least in a state of charge of a lithium ion battery using the lithium-manganese composite oxide as a positive-electrode active material, at least some of iron atoms are pentavalent.

Abstract: The invention discloses a positive electrode active material for a magnesium secondary battery or lithium ion secondary battery, including: a particle including a nucleus and a crystal of vanadium oxide grown from the nucleus as a starting point and having a maximum length of 5 ?m or less in the major axis direction.

Abstract: There is provided a lithium-iron-manganese-based composite oxide capable of providing a lithium-ion secondary battery which has a high capacity retention rate in charge/discharge cycles and in which the generation of a gas caused by charge/discharge cycles is suppressed. A lithium-iron-manganese-based composite oxide having a layered rock-salt structure, wherein at least a part of the surface of a lithium-iron-manganese-based composite oxide represented by the following formula is coated with an oxide of at least one metal selected from the group consisting of La, Pr, Nd, Sm and Eu: LixM1(y-p)MnpM2(z-q)FeqO(2-?) wherein 1.05?x?1.32, 0.33?y?0.63, 0.06?z?0.50, 0<p?0.63, 0.06?q?0.50, 0???0.80, y?p, and z?q; M1 is at least one element selected from Ti and Zr; and M2 is at least one element selected from the group consisting of Co, Ni and Mn.

Abstract: A positive electrode active material, which has a crystallite size ?/crystallite size ? ratio (?/?) of 1 to 1.75 or less, wherein the crystallite size ? is within a peak region of 2?=18.7±1° and the crystallite size ? is within a peak region of 2?=44.6±1°, each determined by a powder X-ray diffraction measurement using Cu-K? ray, and has a composition represented by formula (I) below: Li[Lix(NiaCobMncMd)1-x]O2??(I) wherein 0?x?0.2, 0.3<a<0.7, 0<b<0.4, 0<c<0.4, 0?d<0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

Abstract: A lithium-manganese composite oxide containing a lithium-iron-manganese composite oxide represented by the composition formula: Li1+x?w(FeyNizMn1?y?z)1?xO2??, where 0<x<?, 0?w<0.8, 0<y<1, 0<z<0.5, y+z<1, and 0??<0.5, in which at least in a state of charge of a lithium ion battery using the lithium-manganese composite oxide as a positive-electrode active material, at least some of iron atoms are pentavalent.

Abstract: There is provided a lithium-iron-manganese-based composite oxide capable of providing a lithium-ion secondary battery which has a high capacity retention rate in charge/discharge cycles and in which the generation of a gas caused by charge/discharge cycles is reduced. A lithium-iron-manganese-based composite oxide having a layered rock-salt structure, wherein at least a part of the surface of a lithium-iron-manganese-based composite oxide represented by the following formula (1) is coated with an inorganic material: LixM1(y-p)MnpM2(z-p)FeqO(2-?) (1) (wherein 1.05?x?1.32, 0.33?y?0.63, 0.06?z?0.50, 0<p?0.63, 0.06?q?0.50, 0???0.80, y?p, and z?q; M1 is at least one element selected from Ti and Zr; and M2 is at least one element selected from the group consisting of Co, Ni and Mn).

Abstract: There is provided a lithium-iron-manganese-based composite oxide capable of providing a lithium-ion secondary battery which has a high capacity retention rate in charge/discharge cycles and in which the generation of a gas caused by charge/discharge cycles is suppressed. A lithium-iron-manganese-based composite oxide having a layered rock-salt structure, wherein at least a part of the surface of a lithium-iron-manganese-based composite oxide represented by the following formula is coated with an oxide of at least one metal selected from the group consisting of La, Pr, Nd, Sm and Eu: LixM1(y-p)MnpM2(z-q)FeqO(2-?) wherein 1.05?x?1.32, 0.33?y?0.63, 0.06?z?0.50, 0<p?0.63, 0.06?q?0.50, 0???0.80, y?p, and z?q; M1 is at least one element selected from Ti and Zr; and M2 is at least one element selected from the group consisting of Co, Ni and Mn.

Abstract: A positive electrode active material, which has a crystallite size ?/crystallite size ? ratio (?/?) of 1 to 1.75 or less, wherein the crystallite size ? is within a peak region of 2?=18.7±1° and the crystallite size ? is within a peak region of 2?=44.6±1°, each determined by a powder X-ray diffraction measurement using Cu-K? ray, and has a composition represented by formula (I) below: Li[Lix(NiaCobMncMd)1-x]O2??(I) wherein 0?x?0.2, 0.3<a<0.7, 0<b<0.4, 0<c<0.4, 0?d<0.1, a+b+c+d=1, and M is at least one metal selected from the group consisting of Fe, Cr, Ti, Mg, Al and Zr.

Abstract: A positive electrode active material for a lithium secondary battery, comprising a lithium-containing composite metal oxide in the form of secondary particles formed by aggregation of primary particles capable of being doped and undoped with lithium ions, each of the secondary particles having on its surface a coating layer, the positive electrode active material satisfying the following requirements (1) to (3): (1) the metal oxide has an ?-NaFeO2 type crystal structure of following formula (A): Lia(NibCocM11-b-c)O2??(A) wherein 0.9?a?1.2, 0.9?b<1, 0<c?0.1, 0.9<b+c?1, and M1 represents at least one optional metal selected from Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In and Sn; (2) the coating layer comprises Li and M2, wherein M2 represents at least one optional metal selected from Al, Ti, Zr and W; and (3) the active material has an average secondary particle diameter of 2 to 20 ?m, a BET specific surface area of 0.1 to 2.

Abstract: There is provided a lithium-iron-manganese-based composite oxide capable of providing a lithium-ion secondary battery which has a high capacity retention rate in charge/discharge cycles and in which the generation of a gas caused by charge/discharge cycles is reduced. A lithium-iron-manganese-based composite oxide having a layered rock-salt structure, wherein at least a part of the surface of a lithium-iron-manganese-based composite oxide represented by the following formula (1) is coated with an inorganic material: LixM1(y-p)MnpM2(z-p)FeqO(2-?) (1) (wherein 1.05?x?1.32, 0.33?y?0.63, 0.06?z?0.50, 0<p?0.63, 0.06?q?0.50, 0???0.80, y?p, and z?q; M1 is at least one element selected from Ti and Zr; and M2 is at least one element selected from the group consisting of Co, Ni and Mn).