A silicon-carbon composite material includes a matrix core, a silicon-carbon composite shell formed by uniformly dispersing nano silicon particles in conductive carbon, and a coating layer. The nano silicon particles are formed by high-temperature pyrolysis of a silicon source, and the conductive carbon is formed by high-temperature pyrolysis of an organic carbon source. The coating layer is a carbon coating layer including at least one layer, and the thickness of its single layer is 0.2-3 μm. A silicon-carbon composite material precursor is formed by simultaneous vapor deposition and is then subjected to carbon coating to form the pitaya-like silicon-carbon composite material which has advantages of high first-cycle efficiency, low expansion and long cycle. The grain growth of the silicon material is slowed down during the heat treatment process, the pulverization of the material is effectively avoided, and the cycle performance, conductivity and rate performance of the material are enhanced.

The invention relates to a process for preparing higher halosilanes by disproportionation of lower halosilanes. The invention further relates to a process for preparing higher hydridosilanes from the higher halosilanes prepared by disproportionation. The invention further relates to mixtures containing at least one higher halosilane or at least one higher hydridosilane prepared by the process described. Finally, the invention relates to the use of such a mixture containing at least one higher hydridosilane for producing electronic or optoelectronic component layers or for producing silicon-containing layers.

The invention relates to a process for preparing higher halosilanes by disproportionation of lower halosilanes. The invention further relates to a process for preparing higher hydridosilanes from the higher halosilanes prepared by disproportionation. The invention further relates to mixtures containing at least one higher halosilane or at least one higher hydridosilane prepared by the process described. Finally, the invention relates to the use of such a mixture containing at least one higher hydridosilane for producing electronic or optoelectronic component layers or for producing silicon-containing layers.

A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.

A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.

A poly-crystalline silicon ingot having a bottom and defining a vertical direction includes a plurality of silicon grains grown in the vertical direction, in which the plurality of the silicon grains have at least three crystal orientations; and a nucleation promotion layer comprising a plurality of chips and chunks of poly-crystalline silicon on the bottom, wherein the poly-crystalline silicon ingot has a defect density at a height ranging from about 150 mm to about 250 mm of the poly-crystalline silicon ingot that is less than 15%.

A poly-crystalline silicon ingot having a bottom and defining a vertical direction includes a plurality of silicon grains grown in the vertical direction, in which the plurality of the silicon grains have at least three crystal orientations; and a nucleation promotion layer comprising a plurality of chips and chunks of poly-crystalline silicon on the bottom, wherein the poly-crystalline silicon ingot has a defect density at a height ranging from about 150 mm to about 250 mm of the poly-crystalline silicon ingot that is less than 15%.

A method and system of igniting one or more filaments for silicon production includes applying an output voltage to the one or more filaments using a transformer connected with the one or more filaments. In addition, the method includes supplying, in combination with the application of the output voltage, a current to a primary winding of the transformer via a choke to limit the current to a first predetermined current threshold range. The combination of the supplied current and applied output voltage allows a predetermined output range to be generated from a power supply device initially required to ignite the one or more filaments.

A method and system of igniting one or more filaments for silicon production includes applying an output voltage to the one or more filaments using a transformer connected with the one or more filaments. In addition, the method includes supplying, in combination with the application of the output voltage, a current to a primary winding of the transformer via a choke to limit the current to a first predetermined current threshold range. The combination of the supplied current and applied output voltage allows a predetermined output range to be generated from a power supply device initially required to ignite the one or more filaments.

The present invention relates to a fluidized bed reactor, comprising a reaction tube, a distributor and a heating device, the reaction tube and the distributor at the bottom of the reaction tube composing a closed space, the distributor comprising a gas inlet and a product outlet, and the reaction tube comprising a tail gas outlet and a seed inlet at the top or upper part respectively, characterized in that the reaction tube comprises a reaction inner tube and a reaction outer tube, and the heating device is an induction heating device placed within a hollow cavity formed between the external wall of the reaction inner tube and the internal wall of the reaction outer tube, wherein the hollow cavity is filled with hydrogen, nitrogen or inert gas for protection, and is able to maintain a pressure of about 0.01 to about 5 MPa; and also to a process of producing high purity granular polysilicon using the reactor. The fluidized bed reactor according to the present invention uses induction heating to heat directly the silicon particles inside the reaction chamber, such that the temperature of the reaction tube is lower than that inside the reaction chamber, which accordingly avoids deposition on the tube wall and results in more uniform heating, and thus is useful for large diameter fluidized bed reactors with much increased output for a single reactor.