Abstract: A positive electrode active material having a composition represented by LixNiaCobMncMdO2, wherein, when an inner region, which extends 70% of a diameter from a center of a particle of the positive electrode active material, in a TEM-EDX image of a cross-section of the particle is sectioned into square regions of 10 nm, a proportion of regions at which a concentration of an element represented by M is greater than or equal to 10 mass %, with respect to all regions, is greater than or equal to 1.0%, and in the composition, 0.1?x?1.5, 0.5?a?1.0, 0?b?0.3, 0?c?0.3, a+b+c=1.0, 0.0005?d?0.05, and M represents at least one element selected from the group consisting of Ta, Al, Ba, Pr, La, Y, Sr, Ce, Se, Hf, Rh and Zr.

Abstract: A cathode layer for use in a lithium-ion battery includes, as a cathode active material, single-crystal active materials that are crystalline primary particles containing Li, a transition metal, and O. Each single-crystal active material includes long and short edges. The angle between the long and short edges is 60° or more and 120° or less. The aspect ratio, namely the ratio of the length of the long edge to the length of the short edge, is 1.2 or more. The long edge of each single-crystal active material extends along the (003) plane. The proportion NB/NA is 20% or more, where NA represents the number of the single-crystal active materials, and NB represents the number of the single-crystal active materials in which the direction of the long edge is inclined at an angle of 50° or more and 90° or less with respect to an in-plane direction of the cathode layer.

Abstract: A main object of the present disclosure is to provide a cathode active material with which the increase in resistance due to charge and discharge can be suppressed. The present disclosure achieves the object by providing a cathode active material including: a crystalline primary particle containing Li, TM, which is a transition metal, and O, wherein the cathode active material is an aggregate configured by a plurality of the primary particle; an average particle size of the primary particle in the aggregate is 0.5 ?m or more; and in a pore diameter distribution obtained by a mercury press-in method, a peak is present in a range of 65 nm or more and 300 nm or less.

Abstract: A main object of the present disclosure is to provide a cathode active material with which the increase in resistance in storage is reduced. The present disclosure achieves the object by providing a cathode active material including: a crystalline primary particle containing Li, TM, which is a transition metal, and O, wherein the cathode active material is a single crystalline active material configured by the primary particle; and the cathode active material includes a compound A containing La, Ni, and O, a compound B containing Li, W, and O, and a compound C containing Li, B, P, and O, on a surface of the primary particle.

Abstract: A main object of the present disclosure is to provide a cathode active material with excellent storage capacity durability. The present disclosure achieves the object by providing a cathode active material including: a crystalline primary particle containing Li, TM, which is a transition metal, and O, wherein the cathode active material is a single crystalline active material configured by the primary particle; the cathode active material includes a compound A containing La, Ni, and O, and a compound B containing Li, W, and O, on a surface of the primary particle; and La and W are present inside the primary particle.

Abstract: A main object of the present disclosure is to provide a cathode active material capable of reducing resistance and reducing increase rate of cycle resistance. The present disclosure achieves the object by providing a cathode active material including: a crystalline primary particle containing Li, TM, which is a transition metal, and O, wherein the cathode active material is an aggregate configured by a plurality of the primary particle; and there are a compound A containing La, Ni, and O, and a compound B containing Li, W, and O, on a surface of the primary particle.

Abstract: A main object of the present disclosure is to provide a cathode layer with which the decrease in capacity of a lithium ion battery due to charge and discharge can be suppressed. The present disclosure achieves the object by providing a cathode layer to be used in a lithium ion battery, the cathode layer including: a cathode active material, and an oxygen storing and releasing material, wherein the cathode active material includes a crystalline primary particle containing Li, TM, which is a transition metal, and O; the oxygen storing and releasing material is an oxide including at least one element of Ce and Zr; and a content of the oxygen storing and releasing material in the cathode layer is more than 0.5 weight % and less than 7 weight %.

Abstract: A cathode active material includes a primary particle and a coating. The primary particle includes an olivine phosphate compound. The olivine phosphate compound includes at least one selected from the group consisting of lithium manganese phosphate and lithium manganese iron phosphate. The primary particle is doped with Me. The Me is a typical metal element serving as a divalent cation. The coating covers at least part of a surface of the primary particle. The coating contains carbon. At least one selected from the group consisting of an Me—C bond and an Me—O—C bond is detected by X-ray photoelectron spectroscopy.

Abstract: A positive electrode active material includes powder including single crystal particles. Each of the single crystal particles includes a lithium transition metal composite oxide. The lithium transition metal composite oxide has a crystal structure that belongs to R-3m space group and includes at least nickel. In a scanning electron microscope image of the powder, the single crystal particles do not aggregate and are independent single particles. Each of the single crystal particles has a polyhedral shape. Each of the single crystal particles has a longest side and a short side. The longest side extends along a 003 plane. The short side is connected to an end of the longest side. An interior angle formed between the longest side and the short side ranges from 60° to 120° . A ratio of the longest side to the short side is greater than or equal to 1.10.

Abstract: A cathode active material for a lithium ion secondary battery contains single-crystal particles. A crack group is created in a cross-section of the single-crystal particle. The crack group includes two or more of the cracks. The crack group includes a portion at which two or more cracks extend in parallel. The cathode active material satisfies a relation of “3%?L/D”. “L” indicates a length of the crack. “D” indicates a diameter of a smallest circumscribing circle of the single-crystal particle in the cross-section.

Abstract: A cathode for a lithium-ion secondary battery includes a cathode active material layer. The cathode active material layer contains a cathode active material. The cathode active material contains single-crystal particles. One hundred single-crystal particles randomly sampled from a scanning electron microscope image of a cross-section of the cathode active material layer include at least one first particle including a recess and at least one second particle including a protrusion. The following relationships are satisfied: "0.01 ? d/D1 ? 0.56" and "0.01 ? h/D2 ? 0.58," where "d" represents the depth of the recess of the first particle, "D1" represents the diameter of the minimum circumscribed circle of the first particle, "h" represents the height of the protrusion of the second particle, and "D2" represents the diameter of the minimum circumscribed circle of the second particle.

Abstract: The present disclosure relates to a positive electrode active material for a lithium-ion secondary battery. The positive electrode active material for a lithium-ion secondary battery according to the present disclosure contains secondary particles. The secondary particle includes three or more primary particles. The secondary particles are provided by two-dimensionally arranging three or more primary particles.

Abstract: A positive electrode active material for a lithium-ion secondary battery contains monocrystalline particles. The monocrystalline particle includes a first pyramidal portion and a second pyramidal portion. The first pyramidal portion protrudes in a first direction. The first pyramidal portion has a first outer diameter. The first outer diameter indicates a diameter of a minimum circumscribed circle with respect to the first pyramidal portion. The second pyramidal portion protrudes in a second direction. The second pyramidal portion has a second outer diameter. The second outer diameter indicates a diameter of a minimum circumscribed circle with respect to the second pyramidal portion. The first outer diameter is larger than the second outer diameter. An angle between the first direction and the second direction is greater than 0° and 45° or less.

Abstract: A positive electrode active material includes secondary particles. Each of the secondary particles includes primary particles. Each of the primary particles includes an olivine-type phosphate compound. An open pore is formed in the secondary particle. The open pore is a non-through hole. A cross section of the secondary particle satisfies relationships of “0.9?d/D?10.1” and “1.9?Sd/d?33.4”. “d” represents a maximum depth of the open pore. “D” represents an opening diameter of the open pore. “Sd” represents a diameter of a smallest circumcircle of the cross section of the secondary particle.

Abstract: A positive electrode active material includes secondary particles. Each of the secondary particles includes primary particles. Each of the primary particles includes an olivine-type phosphate compound. A part of a surface of the secondary particle has a depression. At the depression, the surface of the secondary particle is depressed in a shape of a concave surface. A cross section of the secondary particle satisfies a relationship of “0.41?Sa/Ca?0.95”. “Sa” represents an area of the cross section of the secondary particle. “Ca” represents an area of a smallest circumcircle of the cross section of the secondary particle.

Abstract: A positive electrode active material includes tertiary particles. Each of the tertiary particles includes secondary particles. Each of the secondary particles includes primary particles. Each of the primary particles includes lithium manganese iron phosphate.

Abstract: A positive electrode active material comprises tertiary particles. Each of the tertiary particles includes secondary particles. Each of the secondary particles includes primary particles. Each of the primary particles includes an olivine-type phosphate compound. In at least part of the tertiary particle, a vacant space is formed between the secondary particles.

Abstract: In this disclosure, a battery is provided. The electrode includes an electrode current collector and an electrode active material layer, wherein the electrode active material layer includes a single crystal electrode active material and a polycrystalline electrode active material, and the single crystal electrode active material and the polycrystalline electrode active material are each a lithium transition metal composite oxide, and the electrode active material layer includes a first layer including a first surface opposite to the electrode current collector and a second layer including a second surface on the electrode current collector side, wherein the first layer includes the single crystal electrode active material as a main component of the electrode active material, and the second layer includes the polycrystalline electrode active material as a main component of the electrode active material.

Abstract: The cathode active material includes secondary particles. The secondary particle includes a plurality of crystallites. Each of the plurality of crystallites includes a lithium metal composite oxide. A structure of the lithium metal composite oxide is a layered-rocksalt structure. In the cross section of the secondary particle, “2.5?dL/dS?28.2”, “0.125?dL/D”, and “??450” are satisfied. “dL” indicates the major axis diameter of the crystallite. “dS” indicates the minor axis diameter of the crystallite. “D” indicates the maximum Feret diameter of the secondary particles. “?” represents an angle formed between the first straight line and the second straight line. The first straight line is an extension of the major axis diameter of the crystallite. The second straight line passes through the intersection of the circumscribed circle of the secondary particle and the extension line and the center of the circumscribed circle.

Abstract: The cathode active material includes secondary particles. The secondary particle includes a plurality of crystallites. Each of the plurality of crystallites includes a lithium metal composite oxide. A structure of the lithium metal composite oxide is a layered-rocksalt structure. In the cross section of the secondary particle, “2.5?dL/dS?15”, “0.051?dL/D?0.124”, and “??45°” are satisfied. “dL” indicates the major axis diameter of the crystallite. “dS” indicates the minor axis diameter of the crystallite. “D” indicates the maximum Feret diameter of the secondary particles. “?” represents an angle formed between the first straight line and the second straight line. The first straight line is an extension of the major axis diameter of the crystallite. The second straight line passes through the intersection of the circumscribed circle of the secondary particle and the extension line and the center of the circumscribed circle.