Abstract: An object of the present invention is to provide a negative electrode active material having excellent charge/discharge characteristics (charge and discharge capacities, initial coulombic efficiency, and cycle characteristics). The object is achieved by providing a negative electrode active material containing: a silicon-based inorganic compound (a) composed of silicon (excluding zerovalent silicon), oxygen, and carbon; and silicon (zerovalent) (b). The equivalent constituent ratio [Q units/(D units+T units+Q units)] indicating the chemical bonding state (D units [SiO2C2], T units [SiO3C], Q units[SiO4]) of the silicon (excluding zerovalent silicon) present in the silicon-based inorganic compound (a) is within the range of from 0.30 to 0.80 inclusive.

Abstract: An object of the present invention is to provide a negative electrode active material having excellent charge/discharge characteristics (charge and discharge capacities, initial coulombic efficiency, and cycle characteristics). The object is achieved by providing a negative electrode active material containing: a silicon-based inorganic compound (a) composed of silicon (excluding zerovalent silicon), oxygen, and carbon; and silicon (zerovalent) (b). The equivalent constituent ratio [Q units/(D units+T units+Q units)] indicating the chemical bonding state (D units [SiO2C2], T units [SiO3C], Q units[SiO4]) of the silicon (excluding zerovalent silicon) present in the silicon-based inorganic compound (a) is within the range of from 0.30 to 0.80 inclusive.

Abstract: The problem to be solved is to provide a nondrying polymer hydrogel, which is not dried under atmospheric conditions and has excellent mechanical properties, and a method for producing the nondrying polymer hydrogel. A nondrying polymer hydrogel having both excellent nondrying properties and mechanical properties (e.g., excellent elongation properties, compression properties, and surface adhesiveness) can be produced by using a nondrying polymer hydrogel including a deliquescent substance in such a manner that the water vapor pressure shown by the polymer hydrogel is equal to or lower than the water vapor partial pressure in the atmosphere, in particular, by allowing a deliquescent substance to be contained at a high concentration in a polymer hydrogel having a network structure formed by a polymer of a water-soluble radically-polymerizable organic monomer having a specific chemical composition and a delaminated water-swellable clay mineral.

Abstract: The problem to be solved is to provide a nondrying polymer hydrogel, which is not dried under atmospheric conditions and has excellent mechanical properties, and a method for producing the nondrying polymer hydrogel. A nondrying polymer hydrogel having both excellent nondrying properties and mechanical properties (e.g., excellent elongation properties, compression properties, and surface adhesiveness) can be produced by using a nondrying polymer hydrogel including a deliquescent substance in such a manner that the water vapor pressure shown by the polymer hydrogel is equal to or lower than the water vapor partial pressure in the atmosphere, in particular, by allowing a deliquescent substance to be contained at a high concentration in a polymer hydrogel having a network structure formed by a polymer of a water-soluble radically-polymerizable organic monomer having a specific chemical composition and a delaminated water-swellable clay mineral.