The invention relates to material comprising a layered material having the composition Na.sub.x[Mg.sub.3-zLi.sub.y]Si.sub.4O.sub.10(T).sub.2, wherein x is in the range of 0.4 to 0.8, y is in the range of 0.0 to 0.8, 5z is in the range of 0.2 to 0.8, T independent of each occurrence represents F or OH, and x+(3?z)+y?4, wherein the powder X-ray diffraction pattern of the layered material has a 001 peak in the range of 8.00 to 5.88? 2Theta, and wherein the 001 peak has a full width at half of the peak maximum 10 of larger than 0.10?, and wherein the layered material has a Z-average particle size of 500 nm or higher, determined by dynamic laser light scattering on an aqueous dispersion of the material containing at most 1.5% by weight of the material.

The invention relates to material comprising a layered material having the composition Na.sub.x[Mg.sub.3-zLi.sub.y]Si.sub.4O.sub.10(T).sub.2, wherein x is in the range of 0.4 to 0.8, y is in the range of 0.0 to 0.8, 5z is in the range of 0.2 to 0.8, T independent of each occurrence represents F or OH, and x+(3?z)+y?4, wherein the powder X-ray diffraction pattern of the layered material has a 001 peak in the range of 8.00 to 5.88? 2Theta, and wherein the 001 peak has a full width at half of the peak maximum 10 of larger than 0.10?, and wherein the layered material has a Z-average particle size of 500 nm or higher, determined by dynamic laser light scattering on an aqueous dispersion of the material containing at most 1.5% by weight of the material.

A negative electrode active material including silicon-containing composite particles including SiO.sub.x (0<x<2) and a Mg compound or Li compound; and a carbon layer present on a surface of the silicon-containing composite particles. The silicon-containing composite particles have a BET specific surface area of 5 m.sup.2/g to 60 m.sup.2/g, and the negative electrode active material has a BET specific surface area of 2 m.sup.2/g to 15 m.sup.2/g, and a powder conductivity of 0.05 S/cm to 1 S/cm at a powder density of 1.4 g/cc. A negative electrode including the negative electrode active material, a secondary battery including the negative electrode, and a method for preparing the negative electrode active material are also disclosed.

A negative electrode active material including silicon-containing composite particles including SiO.sub.x (0<x<2) and a Mg compound or Li compound; and a carbon layer present on a surface of the silicon-containing composite particles. The silicon-containing composite particles have a BET specific surface area of 5 m.sup.2/g to 60 m.sup.2/g, and the negative electrode active material has a BET specific surface area of 2 m.sup.2/g to 15 m.sup.2/g, and a powder conductivity of 0.05 S/cm to 1 S/cm at a powder density of 1.4 g/cc. A negative electrode including the negative electrode active material, a secondary battery including the negative electrode, and a method for preparing the negative electrode active material are also disclosed.

A method for producing forsterite microparticles having a primary particle size of 1, to 50 nm, as determined through electron microscopy. The method includes spray-drying, in an atmosphere of 50 C. or higher and lower than 300 C., a solution containing a water-soluble magnesium salt and colloidal silica at a mole ratio of magnesium atoms to silicon atoms (Mg/Si) of 2; and subsequently, firing the spray-dried product in air at 800 to 1,000 C.

A method for producing forsterite microparticles having a primary particle size of 1, to 50 nm, as determined through electron microscopy. The method includes spray-drying, in an atmosphere of 50 C. or higher and lower than 300 C., a solution containing a water-soluble magnesium salt and colloidal silica at a mole ratio of magnesium atoms to silicon atoms (Mg/Si) of 2; and subsequently, firing the spray-dried product in air at 800 to 1,000 C.

Disclosed is a transparent self-assembling polymer clay nanocomposite coating that is useful in food, drink and electronic packaging as a gas barrier and on textiles and clothing as a flame retardant coating. The coating includes two main components a water dispersible polymer and a sheet like nanoparticle. The coatings may be applied to any substrate. The coatings are applied sequentially with polymer being applied first followed by the nanoparticles. This sequence results in the self-assembly of a highly ordered nanocomposite film that exhibits high barrier properties and flame retardancy. The desired level of gas barrier or flame retardancy desired can be adjusted by the number of bilayers applied.

Forsterite particles have an average size of 0.1 m to 10 m and a dielectric loss tangent of 0.0003 to 0.0025. Sphericity=(Average particle size (m) measured with a laser diffraction particle size distribution analyzer)/(Average primary particle size (m) calculated by conversion using specific surface area measured by a nitrogen gas adsorption method) may be from 1.0 to 3.3. This method for producing forsterite particles may include: step (A): mixing a magnesium compound as a magnesium source and a silicon compound as a silicon source so MgO/SiO.sub.2 has a molar ratio of 1.90 to 2.10 to prepare particles; step (B): putting the particles prepared in step (A) into a hydrocarbon combustion flame to recover the resulting particles; and step (C): firing the particles obtained in step (B) at 700 C. to 1100 C. The ratio between a resin and the particles may be 1:0.001 to 1000 by mass ratio.

Forsterite particles have an average size of 0.1 m to 10 m and a dielectric loss tangent of 0.0003 to 0.0025. Sphericity=(Average particle size (m) measured with a laser diffraction particle size distribution analyzer)/(Average primary particle size (m) calculated by conversion using specific surface area measured by a nitrogen gas adsorption method) may be from 1.0 to 3.3. This method for producing forsterite particles may include: step (A): mixing a magnesium compound as a magnesium source and a silicon compound as a silicon source so MgO/SiO.sub.2 has a molar ratio of 1.90 to 2.10 to prepare particles; step (B): putting the particles prepared in step (A) into a hydrocarbon combustion flame to recover the resulting particles; and step (C): firing the particles obtained in step (B) at 700 C. to 1100 C. The ratio between a resin and the particles may be 1:0.001 to 1000 by mass ratio.

A method of preparing silicon carbide according to the present invention includes reacting a silicon-containing compound with carbon dioxide, wherein a reducing agent is optionally used.