Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

A Si-containing film forming composition comprising a catalyst and/or a polysilane and a N—H free, C-free, and Si-rich perhydropolysilazane having a molecular weight ranging from approximately 332 dalton to approximately 100,000 dalton and comprising N—H free repeating units having the formula [—N(SiH3)x(SiH2-)y], wherein x=0, 1, or 2 and y=0, 1, or 2 with x+y=2; and x=0, 1 or 2 and y=1, 2, or 3 with x+y=3. Also disclosed are synthesis methods and applications for using the same.

A silicon material can include a silicon aggregate comprising a plurality of porous silicon nanoparticles welded together. The silicon aggregate can optionally have a polyhedral morphology. A method can include: receiving a plurality of porous silicon nanoparticles and cold welding the plurality of porous silicon nanoparticles into an aggregated silicon particle.

The present application provides a system and method for producing a silicon-containing product by using a silicon sludge, which is produced by a cutting silicon material with a diamond wire. The method utilizes a high oxide layer on the surface of a silicon waste particle produced during diamond wire cutting. The surface oxide undergoes a disproportionation reaction with adjacent internal elemental silicon to form silicon monoxide, which is removed in a vapor to achieve a physical chemical reaction with a metal, a halogen gas, a hydrogen halide gas or hydrogen to form silicon-containing products of higher added value. The process realizes the large-scale, high-efficiency, energy-saving, continuous and low-cost complete recycling of silicon waste produced by diamond wire cutting of silicon material.

Disclosed herein are embodiments of producing Si or SiO.sub.x from inexpensive silica sources. In some embodiments, plasma processing can be used to covert the silica sources to the silicon products. Unique morphologies can be formed in some embodiments. In some embodiments, reducing agents, catalysts, and/or salts can be used to provide advantageous properties.

[Problem to be solved] To produce an SiO powder having a rounded spherical particulate shape and a small particle diameter; and further having a low degree of impurity contamination, efficiently and economically.

[Solution] A mixture of Si and SiO.sub.2 as an SiO gas generation raw material 9 is loaded into a crucible 2. The mixture in the crucible 2 is heated under a reduced pressure so as to generate SiO gas. The generated SiO gas is accumulated on a deposition base 5 rotating on the crucible 2. When SiO deposit 10 accumulated on the deposition base 5 is scraped off with a blade 7, a tip of the blade 7 is separated from a surface of the deposition base 5, and in a state in which a portion of the SiO deposit 10 accumulated on the deposition base 5 is left on the deposition base 5, the remaining SiO deposit 10 is scraped off by the blade 7 and collected as an SiO powder 11.

The present application provides a method, a equipment and a system for producing a silicon-containing products by using a silicon sludge which is produced by a diamond wire cutting silicon material. The method of the present application mainly utilizes a high oxide layer on the surface of a silicon waste particle produced during diamond wire cutting. The characteristics are such that the surface oxide disproportionates with adjacent internal elemental silicon to form silicon monoxide to be removed in a vapor to achieve a physical chemical reaction with a metal, a halogen gas, a hydrogen halide gas or hydrogen to form a high value-added silicon-containing products. The process realizes the large-scale, high-efficiency, energy-saving, continuous and low-cost complete recycling of diamond-wire cutting silicon waste.

A negative electrode active material including a negative electrode active material particle, wherein the negative electrode active material particle includes a silicon compound particle comprising a silicon compound (SiO.sub.x: 0.5≤x≤1.6), the silicon compound particle includes crystalline Li.sub.2SiO.sub.3 and Li.sub.2Si.sub.2O.sub.5 in at least part of the silicon compound particle, among a peak intensity A derived from Li.sub.2SiO.sub.3, a peak intensity B derived from Si, a peak intensity C derived from Li.sub.2Si.sub.2O.sub.5, and a peak intensity D derived from SiO.sub.2 which are obtained from a .sup.29Si-MAS-NMR spectrum of the silicon compound particle, the peak intensity A or the peak intensity C is the highest intensity, and the peak intensity A and the peak intensity C satisfy a relationship of the following formula 1,formula 1: C/3≤A≤3C.

A Si-containing film forming composition comprising a catalyst and/or a polysilane and a NH free, C-free, and Si-rich perhydropolysilazane having a molecular weight ranging from approximately 332 dalton to approximately 100,000 dalton and comprising NH free repeating units having the formula [N(SiH3)x(SiH2-)y], wherein x=0, 1, or 2 and y=0, 1, or 2 with x+y=2; and x=0, 1 or 2 and y=1, 2, or 3 with x+y=3. Also disclosed are synthesis methods and applications for using the same.

Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.