Abstract: A positive electrode material for a lithium-ion secondary battery which has high capacity and excellent charge and discharge cycle performance, and a manufacturing method thereof are provided, or a method of manufacturing a positive electrode material with high productivity is provided. The positive electrode material for a lithium-ion secondary battery includes a crystal represented by a crystal structure with a space group R-3m, a first region, and a second region, which is in contact with at least part of an outer side of the first region and whose outer edge corresponds to a surface of the first particle. The ratio of manganese atoms to cobalt atoms in the first region is lower than the ratio of manganese atoms to cobalt atoms in the second region. The ratio of fluorine atoms to oxygen atoms in the first region is lower than the ratio of fluorine atoms to oxygen atoms in the second region.

Abstract: A positive electrode active material that has high capacity and excellent charge and discharge cycle performance for a secondary battery is provided. A positive electrode active material that inhibits a decrease in capacity in charge and discharge cycles is provided. A high-capacity secondary battery is provided. A secondary battery with excellent charge and discharge characteristics is provided. A highly safe or reliable secondary battery is provided. A positive electrode active material contains lithium, cobalt, oxygen, and aluminum and has a crystal structure belonging to a space group R-3m when Rietveld analysis is performed on a pattern obtained by powder X-ray diffraction. In analysis by X-ray photoelectron spectroscopy, the number of aluminum atoms is less than or equal to 0.2 times the number of cobalt atoms.

Abstract: An object is to provide a method for manufacturing a positive electrode active material that achieves high powder properties and high load resistance (e.g., rate performance and output resistance) when used in a lithium-ion secondary battery, within a short manufacturing cycle time and at low cost. To perform heat treatment at temperatures lower than the melting point of magnesium fluorine, lithium fluoride is mixed to melt magnesium fluorine and modify the surface of lithium cobalt oxide powder. By mixing lithium fluoride, magnesium fluorine can be melted at a temperature lower than its melting point, and a positive electrode active material is formed utilizing this eutectic phenomenon.

Abstract: A positive electrode active material for a lithium ion secondary battery which has a large capacity and a good charge-and-discharge cycle performance is provided. The positive electrode active material includes lithium, cobalt, oxygen, and magnesium, and has a compound represented by a layered rock-salt crystal structure. A space group of the compound is represented by R-3m. The compound is a composite oxide in which magnesium is substituted for a lithium position and a cobalt position. The compound is a particle. The magnesium substituted for a lithium position and a cobalt position exists more in the region from the surface to 5 nm than in the region deeper than 10 nm from the surface. More magnesium is substituted for a lithium position than for a cobalt position.

Abstract: A method of producing a honeycomb structure includes a step of forming a ceramic block by bonding a plurality of honeycomb units that have a plurality of cells partitioned by cell walls using a bonding layer, or steps of forming a ceramic block of a single honeycomb unit and providing a coating layer on an outer peripheral portion of the ceramic block. The bonding layer or coating layer is provided as a paste of a bonding material or a coating material including particles of a foaming material having a diameter in a range of approximately 1 ?m to approximately 50 ?m. The method further includes a step of blowing up the foaming material, and a step of evaporating the foaming material and forming bubble marks having a diameter in a range of approximately 100 ?m to approximately 300 ?m.

Abstract: A honeycomb structure includes a ceramic block, a coating layer and at least one of the bonding layer and the coating layer. The ceramic block includes a plurality of honeycomb units that are bonded together and that have a plurality of cells partitioned by cell walls using a bonding layer. The coating layer is provided on an outer peripheral portion of the ceramic block. The at least one of the bonding layer and the coating layer includes bubble marks having a diameter in a range of approximately 100 ?m to approximately 300 ?m and includes no bubble marks having a size exceeding approximately 300 ?m.

Abstract: A method of producing a honeycomb structure includes a step of forming a ceramic block by bonding a plurality of honeycomb units that have a plurality of cells partitioned by cell walls using a bonding layer, or steps of forming a ceramic block of a single honeycomb unit and providing a coating layer on an outer peripheral portion of the ceramic block. The bonding layer or coating layer is provided as a paste of a bonding material or a coating material including particles of a foaming material having a diameter in a range of approximately 1 ?m to approximately 50 ?m. The method further includes a step of blowing up the foaming material, and a step of evaporating the foaming material and forming bubble marks having a diameter in a range of approximately 100 ?m to approximately 300 ?m.