Abstract: A lithium-ion secondary battery positive electrode active material complex, a lithium-ion secondary battery positive electrode, and a lithium-ion secondary battery using the lithium-ion secondary battery positive electrode containing the lithium-ion secondary battery positive electrode active material complex are provided so that a lithium-ion secondary battery having high output properties, excellent durability, and a high energy density can be attained. A positive electrode active material for a lithium-ion secondary battery contains a complex in which a surface of a first positive electrode active material made of a lithium transition metal complex oxide containing nickel is covered with a covering layer containing an olivine type second positive electrode active material on a surface of which carbon is carried and a carbon nanotube.

Abstract: A positive electrode (21) includes a positive electrode current collector (21A), and a positive electrode mixture layer (21B) which is formed on the positive electrode current collector (21A) and contains a positive electrode active material. The positive electrode mixture layer (21B) includes a first positive electrode active material (21B-1) composed of LiVPO4F and a second positive electrode active material (21B-2) composed of LiVP2O7. In addition, a mixing ratio of the first positive electrode active material (21B-1) and the second positive electrode active material (21B-2) contained in the positive electrode mixture layer (21B) is represented by (1?x)LiVPO4F+xLiVP2O7 (x is a mass ratio, 0<x?0.21).

Abstract: Provided is a positive electrode for a lithium ion battery that realizes an increase in energy density and is capable of improving durability. A positive electrode for a lithium ion battery (21) has a positive electrode current collector (21A) and a positive electrode mixture layer (21B) formed on the positive electrode current collector (21A). The positive electrode mixture layer (21B) contains a lithium nickel composite oxide and a metallic phosphate that coats the lithium nickel composite oxide. The lithium nickel composite oxide is represented by a chemical formula LiNixCoyMzO2 (in the formula, M is one or more elements selected from the group consisting of Mn, Al, Mg and W, x+y+z=1 and 0.6?x<1.0). The metallic phosphate is one or more materials selected from the group consisting of VPO4, VP2O7 and VPO4F. The mass ratio of the metallic phosphate to the lithium nickel composite oxide is 0.01 mass % or more and 20 mass % or less.

Abstract: A lithium-ion secondary battery positive electrode active material complex, a lithium-ion secondary battery positive electrode, and a lithium-ion secondary battery using the lithium-ion secondary battery positive electrode containing the lithium-ion secondary battery positive electrode active material complex are provided so that a lithium-ion secondary battery having high output properties, excellent durability, and a high energy density can be attained. A positive electrode active material for a lithium-ion secondary battery contains a complex in which a surface of a first positive electrode active material made of a lithium transition metal complex oxide containing nickel is covered with a covering layer containing an olivine type second positive electrode active material on a surface of which carbon is carried and a carbon nanotube.

Abstract: A positive electrode (21) includes a positive electrode current collector (21A), and a positive electrode mixture layer (21B) which is formed on the positive electrode current collector (21A) and contains a positive electrode active material. The positive electrode mixture layer (21B) includes a first positive electrode active material (21B-1) composed of LiVPO4F and a second positive electrode active material (21B-2) composed of LiVP2O7. In addition, a mixing ratio of the first positive electrode active material (21B-1) and the second positive electrode active material (21B-2) contained in the positive electrode mixture layer (21B) is represented by (1?x)LiVPO4F+xLiVP2O7 (x is a mass ratio, 0<x?0.21).

Abstract: A positive electrode material for lithium-ion secondary battery, a positive electrode for lithium-ion secondary battery, and a lithium-ion secondary battery using the positive electrode for lithium-ion secondary battery including the positive electrode material for lithium-ion secondary battery are provided. A lithium-containing transition metal oxide with a high capacity and an olivine type active substance with a high potential are blended to form the positive electrode material. Specifically, the positive electrode material is formed in which a first positive electrode active substance and a second positive electrode active substance are contained, the first positive electrode active substance is a lithium-transition metal composite oxide containing nickel, and the second positive electrode active substance is an olivine type active substance having 50% or more of a total capacity in a potential area of 4.2-4.1 V when a counter electrode is lithium.