A silicon material can include a composition with at least about 50% silicon, at most about 45% carbon, and at most about 10% oxygen. The silicon material can have an external expansion that is less than about 40%. The silicon material can include silicon nanoparticles, which can cooperatively form clusters. The silicon nanoparticles can be porous.

A porous silicon manufacturing method according to the present invention comprises the steps of: pretreating a silicon precursor and a heat dispersant; and conducting a thermal reduction reaction between the heat dispersant-pretreated silicon precursor and a metal reducing agent by using a rotary reaction chamber. When porous silicon manufactured by the manufacturing method is contained in a secondary battery anode active material and used in secondary batteries, the batteries exhibit high capacity and long lifespan characteristics. The present invention relates to a method for manufacturing porous silicon and a method for manufacturing a secondary battery anode active material containing the porous silicon manufactured thereby, with the aim of solving the problems with silicon materials under development for anode active materials for lithium secondary batteries, including excessive volume expansion during charge/discharge and resultant electrode fracture and lifespan shortening.

A porous silicon manufacturing method according to the present invention comprises the steps of: pretreating a silicon precursor and a heat dispersant; and conducting a thermal reduction reaction between the heat dispersant-pretreated silicon precursor and a metal reducing agent by using a rotary reaction chamber. When porous silicon manufactured by the manufacturing method is contained in a secondary battery anode active material and used in secondary batteries, the batteries exhibit high capacity and long lifespan characteristics. The present invention relates to a method for manufacturing porous silicon and a method for manufacturing a secondary battery anode active material containing the porous silicon manufactured thereby, with the aim of solving the problems with silicon materials under development for anode active materials for lithium secondary batteries, including excessive volume expansion during charge/discharge and resultant electrode fracture and lifespan shortening.

Chlorosilanes are produced in exalted yield in a fluidized bed process when the reactor hydraulic diameter, Sauter particle diameter, and superficial gas velocity are used to define a parameter space as a function of Reynolds number and Archimedes number.

Chlorosilanes are produced in exalted yield in a fluidized bed process when the reactor hydraulic diameter, Sauter particle diameter, and superficial gas velocity are used to define a parameter space as a function of Reynolds number and Archimedes number.

A method of improving the operation of polysilicon fluidized bed reactors is disclosed. The present disclosure is directed to the optimization of axial temperature gradients in gas-solid fluidized bed systems. Varying the width of the particle size distribution in the reactor alters the temperature gradient within the reactor, thereby providing a means of a better control of internal temperature profiles and hence better reactor performance.

A method of improving the operation of polysilicon fluidized bed reactors is disclosed. The present disclosure is directed to the optimization of axial temperature gradients in gas-solid fluidized bed systems. Varying the width of the particle size distribution in the reactor alters the temperature gradient within the reactor, thereby providing a means of a better control of internal temperature profiles and hence better reactor performance.

The present invention relates to silicon-based powders and a method for producing the silicon-based powders. The method for producing the silicon-based powders includes a hydrolysis step of a silicon precursor having an alkoxy group, a condensation step and a drying step. By a specific weight ratio of water to the silicon precursor having the alkoxy group and a silicon precursor having a secondary amino group and an alkyl group, in the method for producing the silicon-based powders, the condensation step can be performed without organic solvents, and a modification on silicon-based gels can be performed to enhance a safety of processes and a hydrophobicity of the resulted silicon-based powders, and decrease a thermal conductivity and a bulk density of the resulted silicon-based powders.

The present invention relates to silicon-based powders and a method for producing the silicon-based powders. The method for producing the silicon-based powders includes a hydrolysis step of a silicon precursor having an alkoxy group, a condensation step and a drying step. By a specific weight ratio of water to the silicon precursor having the alkoxy group and a silicon precursor having a secondary amino group and an alkyl group, in the method for producing the silicon-based powders, the condensation step can be performed without organic solvents, and a modification on silicon-based gels can be performed to enhance a safety of processes and a hydrophobicity of the resulted silicon-based powders, and decrease a thermal conductivity and a bulk density of the resulted silicon-based powders.

Provided is a composite anode active material including: a carbonaceous material; a metal alloyable with lithium, located on a surface of the carbonaceous material; and a silicon coating layer located on a surface of the carbonaceous material, on a surface of the metal alloyable with lithium, or a combination thereof.