Abstract: In a nonaqueous electrolyte secondary battery which includes an electrode assembly that includes a positive electrode including a positive electrode current collector and a positive electrode mixture layer, a negative electrode including a negative electrode current collector and a negative electrode mixture layer, and a separator, the positive electrode mixture layer contains Ni in a proportion of not less than 85 mol % relative to the total molar amount of metal element(s) except lithium, and includes a lithium transition metal oxide bearing on the surface thereof an attached element belonging to Group VI of the periodic table. The negative electrode mixture layer includes a carbon material and a silicon compound. The surface pressure present on a plane in which the positive electrode and the negative electrode are opposed to each other through the separator is not less than 0.1 MPa/cm2.

Abstract: There is provided a negative electrode active material for a nonaqueous electrolyte secondary battery, the negative electrode active material including a base particle containing Si and SiO2, a mixed phase coating that covers a surface of the base particle and contains SiO2 and carbon, and a carbon coating that covers a surface of the mixed phase coating. The base particle is preferably formed of SiOX (0.5?X?1.5). The mixed phase coating preferably contains carbon dispersed in a phase formed of SiO2. The cycle characteristics of a nonaqueous electrolyte secondary battery including negative electrode active material particles containing Si and SiO2 are improved.

Abstract: The initial charge/discharge efficiency and cycle characteristics of a nonaqueous electrolyte secondary battery are improved. Provided is a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a porous layer placed on the negative electrode, a separator, and a nonaqueous electrolyte. The porous layer has flat voids. The minor axis direction of each flat void is perpendicular to the plane direction of the porous layer and the major axis direction of the flat void is parallel to the plane direction of the porous layer. The ratio of the major axis to the minor axis of the flat void preferably ranges from 1.4 to 2.2.

Abstract: A negative electrode for nonaqueous electrolyte secondary batteries is provided which includes SiOx and allows the cycle characteristics of batteries to be enhanced. A negative electrode according to an example embodiment includes a negative electrode current collector and a negative electrode mixture layer disposed on the current collector. The negative electrode mixture layer includes SiOx (0.5?x?1.5) particles having a carbon coating on a particle surface, carbonaceous active material particles, and a compound having at least one of a carboxyl group and a hydroxyl group and having an average number of etherifying agent moieties present per unit molecule of not more than 0.8. The carbon coating includes a first coating disposed on the surface of the SiOx and a second coating disposed on the first coating and including carbon having higher crystallinity than the carbon forming the first coating.

Abstract: A non-aqueous electrolyte secondary battery containing a silicon material, wherein the negative-electrode active material can constitute a non-aqueous electrolyte secondary battery having high charge capacity, high initial charge/discharge efficiency, and good cycle characteristics. A negative-electrode active material particle according to an embodiment includes a lithium silicate phase represented by Li2zSiO(2+z) {0<z<2} and particles dispersed in the lithium silicate phase. Each of the particles includes a silicon (Si) core particle and a surface layer formed of an iron alloy containing Si (FeSi alloy). In an XRD pattern of the negative-electrode active material particle obtained by XRD measurement, a diffraction peak of the FeSi alloy at 2?=approximately 45 degrees has a half-width of 0.40 degrees or more, and a diffraction peak of a Si (111) plane at 2?=approximately 28 degrees has a half-width of 0.40 degrees or more.

Abstract: The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle (10) according to an embodiment includes a lithium silicate phase (11) represented by Li2zSiO(2+z) {0<z<2} and silicon particles (12) dispersed in the lithium silicate phase (11). The silicon particles (12) have a crystallite size of 40 nm or less. The crystallite size is calculated using the Scherrer equation from the half-width of the diffraction peak of the Si (111) plane in an XRD pattern obtained by XRD measurement of the negative-electrode active material particle 10.

Abstract: A non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material has improved initial charge/discharge efficiency. A negative-electrode active material particle (10) according to an embodiment contains a base particle (13), which includes a lithium silicate phase (11) represented by Li2zSiO(2+z) {0<z<2} and silicon particles (12) dispersed in the lithium silicate phase (11). The base particle (13) has a porosity of 25% or less, preferably 15% or less.

Abstract: The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle (10) according to an embodiment includes a lithium silicate phase (11) represented by Li2zSiO(2+z) {0<z<2} and silicon particles (12) dispersed in the lithium silicate phase (11). A lithium silicate constituting the lithium silicate phase has a crystallite size of 40 nm or less. The crystallite size is calculated using the Scherrer equation from the half-width of a diffraction peak of a (111) plane of the lithium silicate in an XRD pattern obtained by XRD measurement of the negative-electrode active material particle 10.

Abstract: The initial charge/discharge efficiency and cycle characteristics of a non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material are improved. A negative-electrode active material particle (10) according to an embodiment contains a base particle (13), which includes a lithium silicate phase (11) represented by Li2zSiO(2+z) {0<z<2} and silicon particles (12) dispersed in the lithium silicate phase (11). The symmetry determined by an image analysis of a backscattered electron image of a cross section of the base particle (13) is 1.5 or less. The symmetry refers to the ratio (b/a) of the half width at half maximum b of a peak on the high-gray-scale side to the half width at half maximum a of the peak on the low-gray-scale side in a histogram of color distinction based on 256 gray levels for each pixel of the backscattered electron image.

Abstract: Provided are a positive electrode active material capable of suppressing the reduction in capacity of a battery and the generation of gas during storage at high temperature in a charged state and a nonaqueous electrolyte secondary battery including the positive electrode active material. A positive electrode active material particle (20) includes a lithium transition metal oxide particle (21) containing a halogen atom and rare-earth compound particles (22) attached to the surface of the lithium transition metal oxide particle (21). The amount of the halogen atom present on the surface of the lithium transition metal oxide particle (21) is 5 mass percent or less of the total amount of the halogen atom contained in the lithium transition metal oxide particle (21). A rare-earth element making up the rare-earth compound particles (22) is one other than yttrium and scandium.

Abstract: A non-aqueous electrolyte secondary battery that contains a silicon material as a negative-electrode active material has improved cycle life. A negative-electrode active material particle (10) according to an embodiment includes a lithium silicate phase (11) represented by Li2zSiO(2+z) (0<z<2), silicon particles (12) dispersed in the lithium silicate phase (11), and a metallic compound (15) (other than lithium compounds and silicon oxides) dispersed in the lithium silicate phase (11). The metallic compound (15) is preferably selected from zirconium oxide, aluminum oxide, zirconium carbide, tungsten carbide, and silicon carbide.

Abstract: In a nonaqueous electrolyte secondary battery containing a silicon material as a negative electrode active material, the initial charge-discharge efficiency is improved. Negative electrode active material particles (10) according to an embodiment each contain a lithium silicate phase (11) represented by Li2zSiO(2+z) (where 0<z<2) and silicon particles (12) dispersed in the lithium silicate phase (11). In base particles (13) each containing the lithium silicate phase (11) and the silicon particles (12), preferably, a peak originating from SiO2 is not observed at 2?=25° in an XRD pattern obtained by XRD measurement of the particles.

Abstract: A negative electrode for a nonaqueous electrolyte secondary battery according to one aspect of the present invention includes a negative electrode mixture layer that contains a binder and a negative electrode active material particle that forms an alloy with lithium and is formed on a current collector. The negative electrode mixture layer includes a base portion near the current collector and pillar-shaped portions formed on the base portion. A negative electrode for a nonaqueous electrolyte secondary battery according to another aspect of the present invention includes a negative electrode mixture layer that contains a binder and a negative electrode active material particle that forms an alloy with lithium and is formed on a current collector. The negative electrode mixture layer includes pillar-shaped portions and the particle diameter of the negative electrode active material particle is 20% or less of the maximum diameter of the pillar-shaped portions.

Abstract: There are provided a negative electrode for a nonaqueous electrolyte secondary battery having excellent initial efficiency and good moldability of pillar portions included in a negative electrode mixture layer, and a nonaqueous electrolyte secondary battery. A negative electrode (20) for a nonaqueous electrolyte secondary battery according to one aspect of the present invention includes a negative electrode current collector (21) and a negative electrode mixture layer (22) formed on the negative electrode current collector (21) and containing a binder and a negative electrode active material particle that forms an alloy with lithium. The negative electrode mixture layer (22) includes a base portion (22a) near the negative electrode current collector (21) and pillar portions (22b) formed on the base portion (21a). The binder contains a polyimide resin. The polyimide resin has an average molecular weight of 60000 or more.

Abstract: The cycle characteristics of a nonaqueous electrolyte secondary battery including negative electrode active material particles containing Si and SiO2 are improved. There is provided a negative electrode active material for a nonaqueous electrolyte secondary battery, the negative electrode active material including a base particle containing Si and SiO2, a mixed phase coating that covers a surface of the base particle and contains SiO2 and carbon, and a carbon coating that covers a surface of the mixed phase coating. The base particle is preferably formed of SiOX (0.5?X?1.5). The mixed phase coating preferably contains carbon dispersed in a phase formed of SiO2.

Abstract: An object is to improve the safety of a non-aqueous electrolyte secondary battery at the time of the internal short circuit. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode includes a current collector and a positive electrode active material layer formed on the current collector. The current collector includes a metal foil having a roughened surface. The negative electrode includes a silicon-containing negative electrode active material. The metal foil is preferably a metal foil containing aluminum. The metal foil preferably has a surface roughness Ra of 0.1 to 2.0 ?m.

Abstract: Dissolution of cobalt from a positive electrode active material is suppressed. Disclosed is a positive electrode active material for a nonaqueous electrolyte secondary battery that contains a lithium transition metal oxide. Fluorine and at least one element selected from zirconium, titanium, aluminum, magnesium, and rare earth elements adhere to the surface of the lithium transition metal oxide, and the lithium transition metal oxide contains cobalt. The lithium transition metal oxide has an average particle diameter of 10 ?m or less.

Abstract: The cycle characteristics of nonaqueous electrolyte secondary batteries are improved. A negative electrode for nonaqueous electrolyte secondary batteries includes a negative electrode mixture layer on a negative electrode collector. The negative electrode mixture layer contains SiOX (0.5?X?1.5) particles and graphite particles, and the SiOX particles are covered with a cellulose-containing material. The negative electrode mixture layer contains a thickener and a binder, and the thickener contains at least one of a carboxyalkyl cellulose, a hydroxyalkyl cellulose, and an alkoxycellulose each having a degree of etherification of 0.8 or more.

Abstract: The high-temperature storage characteristics of nonaqueous electrolyte secondary batteries are improved. A negative electrode for nonaqueous electrolyte secondary batteries includes a negative electrode collector and a negative electrode mixture layer. The negative electrode mixture layer contains silicon-containing particles, graphite particles, and carboxymethyl cellulose ammonium salt, and the amount of NH3 in the negative electrode mixture layer is 350 ?g or less per g of the negative electrode mixture layer. The silicon-containing particles preferably have a conductive carbon material layer with which at least part of the surfaces thereof is covered. The silicon-containing particles preferably include SiOX (0.5?X?1.5) particles.

Abstract: Provided is a negative electrode active material, containing at least silicon, for nonaqueous electrolyte secondary batteries. Since the negative electrode active material contains silicon, the negative electrode active material has high capacity and excellent cycle characteristics. A negative electrode active material for nonaqueous electrolyte secondary batteries contains at least silicon. At least, one portion of the surface of each of primary particles containing silicon is covered with an inert phase made of a silicon compound with a silicon oxidation number higher than that of the silicon, a metal-silicon alloy, or metal. The primary particles containing silicon may form secondary particles. The silicon compound with a silicon oxidation number higher than that of silicon is preferably Li2Si2O5, Li2SiO3, or Li4SiO4. Furthermore, the metal-silicon alloy is preferably FeSi and the metal is preferably Ti. Furthermore, the crystallite size of silicon is 500 ? or less.