Abstract: According to one embodiment, provided is an electrode group having a flat structure including a flat portion, that includes a wound body and a fixing tape wound around the wound body. The wound body is configured of a stack wound 50 turns or more with a center thereof positioned along a first direction, where the stack includes a positive electrode, a negative electrode, and a separator. In a second direction intersecting a principal surface in the flat portion, a swollen-state thickness TS when impregnated with propylene carbonate and a dry thickness TD satisfy 1.01<TS/TD<1.02. A protrusion width W at both ends in the first direction, which corresponds to a clearance between the positive and negative electrode, is within a range of 0.4 mm or more and 1 mm or less.

Abstract: According to one embodiment, a lithium ion secondary battery is provided. The lithium ion secondary battery includes a negative electrode containing a negative electrode active material-containing layer, a positive electrode, and an electrolyte containing Li ions and Na ions. The negative electrode active material-containing layer contains a Na-containing titanium composite oxide. A ratio (WE/WA) of an Na amount WE (g/g) in the electrolyte to an Na amount WA (g/g) in the negative electrode active material-containing layer satisfies Formula (1) below: 1×10?1?WE/WA?1×105??(1).

Abstract: An active material includes an Nb2TiO7 phase and at least one Nb-rich phase selected from an Nb10Ti2O29 phase, an Nb14TiO37 phase, and an Nb24TiO64 phase. The active material satisfies a peak intensity ratio represented by the following Formula (1): 0<IB/IA?0.25 (1). In Formula (1), IA is a peak intensity of the maximum peak attributed to the Nb2TiO7 phase and appealing at 2? of 26.0±0.1° in a wide angle X-ray diffraction pattern under CuK? rays as an X-ray source, and IB is a peak intensity of the maximum peak attributed to the at least one Nb-rich phase and appearing at 2? of 24.9±0.2° in the diffraction pattern.

Abstract: According to one embodiment, an electrode including an active material-containing layer and a film is provided. The active material-containing layer contains an active material containing a titanium-containing oxide. The film is present on at least a part of a surface of the active material-containing layer. The film contains fluorine, an organic atom, and a metal ion. The fluorine includes fluorine bonded to the organic atom and fluorine bonded to the metal ion. The film satisfies a relationship of following formula (1), where F1 is a proportion of the fluorine bonded to the organic atom, and F2 is a proportion of the fluorine bonded to the metal ion: 0.1?F2/F1?0.6??(1).

Abstract: A nonaqueous electrolyte battery electrode according to an embodiment includes a current collector and a mixed layer formed on one surface or both surfaces of the current collector. The mixed layer includes an active material and a binding agent. The ratio I2/I1 of the highest peak intensity I2 in peaks appearing in the wavelength range of 1400 to 1480 cm?1 to the highest peak intensity I1 in peaks appearing in the wavelength range of 2200 to 2280 cm?1 is 10 or more and 20 or less in an infrared absorption spectrum measured according to a total reflection measurement method. Alternatively, in the mixed layer, the ratio I3/I2 of the highest peak intensity I3 in peaks appearing in the wavelength range of 1650 to 1850 cm?1 to the highest peak intensity I2 in peaks appearing in the wavelength range of 1400 to 1480 cm?1 is 0.1 or more and 0.8 or less in an infrared absorption spectrum measured according to a total reflection measurement method.

Abstract: According to one embodiment, an electrode is provided. The electrode includes an active material-containing layer. The active material-containing layer includes an Na-containing niobium-titanium composite oxide having an orthorhombic crystal structure. The active material-containing layer satisfies I2/I1?1. I1 is an intensity of a peak P1 appearing in a binding energy range of 289 eV to 292 eV in an X-ray photoelectron spectroscopy spectrum of the active material-containing layer. I2 is an intensity of a peak P2 appearing in a binding energy range of 283 eV to 285 eV in the X-ray photoelectron spectroscopy spectrum of the active material-containing layer.

Abstract: According to one embodiment, an active material is provided. The active material includes an Nb2TiO7 phase and at least one Nb-rich phase selected from the group consisting of an Nb10Ti2O29 phase, an Nb14TiO37 phase, and an Nb24TiO64 phase. The active material satisfies a peak intensity ratio represented by the following Formula (1). 0<IB/IA?0.25??(1) In Formula (1), IA is a peak intensity of the maximum peak attributed to the Nb2TiO7 phase and appearing at 2? of 26.0±0.1° in a wide angle X-ray diffraction pattern under CuK? rays as an X-ray source. IB is a peak intensity of the maximum peak attributed to the at least one Nb-rich phase and appearing at 2? of 24.9±0.2° in the diffraction pattern.

Abstract: According to one embodiment, an electrode including an active material-containing layer and a film is provided. The active material-containing layer contains an active material containing a titanium-containing oxide. The film is present on at least a part of a surface of the active material-containing layer. The film contains fluorine, an organic atom, and a metal ion. The fluorine includes fluorine bonded to the organic atom and fluorine bonded to the metal ion. The film satisfies a relationship of following formula (1), where F1 is a proportion of the fluorine bonded to the organic atom, and F2 is a proportion of the fluorine bonded to the metal ion: 0.1?F2/F1?0.6??(1).

Abstract: According to one embodiment, a lithium ion secondary battery is provided. The lithium ion secondary battery includes a negative electrode containing a negative electrode active material-containing layer, a positive electrode, and an electrolyte containing Li ions and Na ions. The negative electrode active material-containing layer contains a Na-containing titanium composite oxide. A ratio (WE/WA) of an Na amount WE (g/g) in the electrolyte to an Na amount WA (g/g) in the negative electrode active material-containing layer satisfies Formula (1) below: 1×10?1?WE/WA?1×105??(1).

Abstract: According to one embodiment, an electrode is provided. The electrode includes an active material-containing layer. The active material-containing layer includes an Na-containing niobium-titanium composite oxide having an orthorhombic crystal structure. The active material-containing layer satisfies I2/I1?1. I1 is an intensity of a peak P1 appearing in a binding energy range of 289 eV to 292 eV in an X-ray photoelectron spectroscopy spectrum of the active material-containing layer. I2 is an intensity of a peak P2 appearing in a binding energy range of 283 eV to 285 eV in the X-ray photoelectron spectroscopy spectrum of the active material-containing layer.

Abstract: According to one embodiment, a nonaqueous electrolyte battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes positive electrode active material secondary particles and a layer. An average secondary particle size of the positive electrode active material secondary particles is from 3 ?m to 25 ?m. The layer covers at least a portion of surfaces of the positive electrode active material secondary particles. The layer contains a lithium titanium oxide and has a thickness of 3 nm to 30 nm. A shortest distance between the positive electrode and the negative electrode is 12 ?m or less.

Abstract: A nonaqueous electrolyte battery electrode according to an embodiment includes a current collector and a mixed layer formed on one surface or both surfaces of the current collector. The mixed layer includes an active material and a binding agent. The ratio I2/I1 of the highest peak intensity I2 in peaks appearing in the wavelength range of 1400 to 1480 cm?1 to the highest peak intensity I1 in peaks appearing in the wavelength range of 2200 to 2280 cm?1 is 10 or more and 20 or less in an infrared absorption spectrum measured according to a total reflection measurement method. Alternatively, in the mixed layer, the ratio I3/I2 of the highest peak intensity I3 in peaks appearing in the wavelength range of 1650 to 1850 cm?1 to the highest peak intensity I2 in peaks appearing in the wavelength range of 1400 to 1480 cm?1 is 0.1 or more and 0.8 or less in an infrared absorption spectrum measured according to a total reflection measurement method.