A porous amorphous silicon which enables improvement in battery performances such as charge/discharge efficiency and battery capacity when used as the anode material; a method for producing a porous amorphous silicon, capable of producing a porous amorphous silicon composed entirely of amorphous silicon at relatively low cost in a short time; and a secondary battery using the porous amorphous silicon as the anode material. A molten metal containing metal and silicon is cooled at a cooling rate of 10.sup.6 K/sec or more to form an eutectic alloy including the metal and the silicon, and then the metal is selectively eluted from the eutectic alloy with an acid or an alkali to obtain a porous amorphous silicon. The porous amorphous silicon has a lamellar or columnar structure having a mean lamellar diameter or a mean column diameter of 1 nm to 100 nm.

Provided are a silicene quantum dots-containing siloxene thin film and a preparation method therefor, which belong to the field of fluorescent functional nanomaterials. A siloxene thin film embedded with silicene quantum dots is prepared by uniformly mixing CaSi.sub.2 with a decalcification organic solvent and a transition metal chloride catalyst in a proportion, performing acid washing, and then performing ultrasonic dispersion. The thickness of such siloxene thin film is less than 1 to 2.5 nm, the size of the silicene quantum dots is 2 to 5 nm. In addition, the siloxene thin film has strong fluorescence emission performance in a blue light region, has a pseudodirect band gap, and shows a good application prospect in the fields of photoelectricity and the like.

Provided are a silicene quantum dots-containing siloxene thin film and a preparation method therefor, which belong to the field of fluorescent functional nanomaterials. A siloxene thin film embedded with silicene quantum dots is prepared by uniformly mixing CaSi.sub.2 with a decalcification organic solvent and a transition metal chloride catalyst in a proportion, performing acid washing, and then performing ultrasonic dispersion. The thickness of such siloxene thin film is less than 1 to 2.5 nm, the size of the silicene quantum dots is 2 to 5 nm. In addition, the siloxene thin film has strong fluorescence emission performance in a blue light region, has a pseudodirect band gap, and shows a good application prospect in the fields of photoelectricity and the like.

An embodiment of the present invention provides a method for preparing a silicon-carbon-graphene composite, comprising the steps of: (step 1) adding a carbon precursor solution to silicon and performing wet grinding so as to prepare a suspension: (step 2) forming a silicon-carbon composite by spray drying the suspension; and (step 3) spray drying and heat treating a solution comprising the silicon-carbon composite and graphene oxide.

An embodiment of the present invention provides a method for preparing a silicon-carbon-graphene composite, comprising the steps of: (step 1) adding a carbon precursor solution to silicon and performing wet grinding so as to prepare a suspension: (step 2) forming a silicon-carbon composite by spray drying the suspension; and (step 3) spray drying and heat treating a solution comprising the silicon-carbon composite and graphene oxide.

A solution and method of creating such for producing silicon nanowires or silicon nano-plates. The solution comprising distilled water, Potassium Hydroxide (KOH), at least one catalyst, Sodium Methyl Siliconate (CH.sub.5NaO.sub.3Si), Ethylenediaminetetraacetic Acid (EDTA), which act as a first chelating agent, Sodium Diethyldithiocarbamate (C.sub.5H.sub.10NS.sub.2Na), which acts as a second chelating agent, and Dimethylacrylic Acid, which acts as a buffer that is able to regulate the amount of silicon nanowires or plates formed and to prevent agglomeration. The concentration of the Sodium Diethyldithiocarbamate in the solution is greater than concentration of the EDTA in the solution for forming a plurality of thick and short nanowires, and the concentration of the Sodium Diethyldithiocarbamate in the solution is less than the concentration of the EDTA in the solution for forming a plurality of thin and long nanowires.

A solution and method of creating such for producing silicon nanowires or silicon nano-plates. The solution comprising distilled water, Potassium Hydroxide (KOH), at least one catalyst, Sodium Methyl Siliconate (CH.sub.5NaO.sub.3Si), Ethylenediaminetetraacetic Acid (EDTA), which act as a first chelating agent, Sodium Diethyldithiocarbamate (C.sub.5H.sub.10NS.sub.2Na), which acts as a second chelating agent, and Dimethylacrylic Acid, which acts as a buffer that is able to regulate the amount of silicon nanowires or plates formed and to prevent agglomeration. The concentration of the Sodium Diethyldithiocarbamate in the solution is greater than concentration of the EDTA in the solution for forming a plurality of thick and short nanowires, and the concentration of the Sodium Diethyldithiocarbamate in the solution is less than the concentration of the EDTA in the solution for forming a plurality of thin and long nanowires.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 μm and about 30 μm and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 μm and about 30 μm and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

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.