A method can include milling a plurality of silicon particles to form a plurality of milled silicon particles. The milled silicon particles can optionally include collecting the milled silicon particles, powdering the milled silicon particles, and milling the milled silicon particles a second time.

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.

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.

A negative electrode active material including negative electrode active material particles, wherein the negative electrode active material particles contain silicon compound particles containing a silicon compound, the silicon compound particles contain Li.sub.2SiO.sub.3, at least a part of a surface of the silicon compound particles is covered with a carbon layer, and a surface layer of the negative electrode active material particles contains a substance having a carboxylic acid structure. Provided by this configuration is a negative electrode active material capable of increasing battery capacity due to improved initial efficiency and capable of realizing satisfactory battery cycle characteristics.

An object of the present invention is to provide a silicon monoxide gas generating raw material in which a reaction that generates a silicon monoxide (SiO) gas is hardly inhibited. The silicon monoxide gas generating raw material according to the present invention has a water content of 0.6 wt % or less.

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.

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.

The present invention discloses an equipment and process for preparing silicon oxides, and relates to the field of chemical equipments. Said equipment comprises at least one tank having opening(s) at at least one end thereof and comprising a reaction unit and a collection unit, wherein the reaction unit is used for placing raw materials therein; and the collection unit is used for placing a collector therein which is placed at the opening end of the tank; and the reaction unit is placed away from the opening end of the tank and placed inside a heating furnace; the collection unit and opening(s) are both placed outside the heating furnace; the tank is vacuumized via a port; and a tank lid is used for opening or closing the opening(s) of the tank. The preparation process uses such equipment. The present invention solves the problems of great energy consumption and low efficiency caused by the fact that the previous equipment and process for preparing silicon oxides are unable to achieve continuous production.

A method for manufacturing porous silicon can include reducing unpurified silica in the presence of a reducing agent to prepare a porous silicon material. The method of manufacture can optionally include purifying a silica, exposing the silica to reaction modifiers, purifying the mixture of the silica and reaction modifiers, comminuting the silica, purifying the silicon, coating the silicon, post-processing the silicon, and/or any suitable steps.

A process for the preparation of nanofilament particles of SiO.sub.x in which x is between 0.8 and 1.2, the process comprising: a step consisting of a fusion reaction between silica (SiO.sub.2) and silicon (Si), at a temperature of at least about 1410° C., to produce gaseous silicon monoxide (SiO); and a step consisting of condensation of the gaseous SiO to produce the SiO.sub.x nanofilament particles. The process may also comprising using carbon.