3756results about "Silicon compounds" patented technology

The invention discloses a silicon-carbon negative electrode material, porous carbon and a preparation method, the porous carbon is prepared by mixing ammonium fluoride and a pre-carbonized material to prepare a premix; and putting the premix in an inert atmosphere, and carrying out pre-activation, drying, carbonization, activation and crushing treatment to obtain the composite material. And uniformly depositing the nano silicon particles into the porous carbon skeleton through a mature CVD (Chemical Vapor Deposition) process to obtain the silicon-carbon composite material. Fluorine and nitrogen co-doping modification can increase the defect degree of a carbon skeleton, efficiently relieve mechanical stress accompanied by lithium storage volume expansion of the silicon negative electrode in a micro scale, provide abundant lithium ion transport and mass transfer channels and enhance the conductivity of porous carbon, and ammonium fluoride is used as a supplementary activator besides water vapor, so that the porosity of the porous carbon is further improved, and the conductivity of the porous carbon is improved. An effective space is provided for uniform deposition of silicon, the fluorine-containing carbon layer can induce formation of a high-stability SEI film rich in LiF on the surface of the nano silicon material, and the interface stability and coulombic efficiency of the silicon negative electrode are further improved.

The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.

The invention discloses metal element-doped nano silicon carbon as well as a preparation method and application thereof, and relates to the field of negative electrode materials. The nano silicon carbon takes porous carbon as a carbon skeleton, and the porous carbon is sequentially attached with nano silicon and coated with a carbon material layer through a chemical vapor deposition method; the porous carbon is prepared by carbonizing resin containing metal nitride after alkali activation and pore forming, and the resin containing the metal nitride is prepared by condensation polymerization of a phenolic compound, an aldehyde compound and the metal nitride in the presence of a catalyst. The porous carbon is doped with the metal nitride in the resin polycondensation process, the conductivity of the nano silicon carbon is effectively improved, the powder resistance is reduced, holes in the surface of the porous carbon provide more expansion space for deposited nano silicon, a carbon material layer formed by subsequent deposition and coating provides a protection effect, the reaction between silicon and an electrolyte can be inhibited, and the service life of the nano silicon carbon is prolonged. A stable SEI film is formed, the cycling stability of the material is improved, the volume expansion rate of a pole piece is inhibited, and the cycling life and the stability of the battery are improved.

The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.

The invention provides a doped electrode material based on porous silicon carbon and a preparation method thereof.The preparation method comprises the steps that a resin base material is smashed and then put into a high-temperature furnace to be subjected to a carbonization process, the carbonization temperature ranges from 300 DEG C to 1500 DEG C, an alkaline additive, a phosphorus source material and a nitrogen source material are sequentially added in the temperature interval, and phosphorus-nitrogen co-doped porous carbon is obtained; the preparation method comprises the following steps: mixing a silicon dioxide microsphere template into phosphorus-nitrogen co-doped porous carbon, adding a first coating carbon source to carry out first coating treatment, and etching the silicon dioxide microsphere template by using an etching solution to obtain a prefabricated object with a cavity structure; and putting the prefabricated object with the cavity structure into a fluidized bed reactor, introducing silicon source gas and a surface activation auxiliary agent, carrying out deposition at 400-550 DEG C, and then adding a second coating carbon source to carry out secondary coating treatment, thereby obtaining the doped electrode material based on porous silicon carbon. Therefore, the expansion coefficient of the electrode material is effectively reduced, and the rate capability is improved.

A silicon-carbon material, a preparation method therefor, a secondary battery, and an electric device. The silicon-carbon material comprises silicon-carbon composite particles; the silicon-carbon composite particles comprise a porous carbon material, nano-silicon grains and a silicon carbide material layer; the porous carbon material is provided with through pores, the nano-silicon grains are located in the through pores, and the silicon carbide material layer is partially located on through pore walls; the grain size of the nano-silicon grains is not smaller than the average pore diameter of the porous carbon material. The silicon-carbon material is used as an active material of a negative electrode sheet, thereby improving the cycle performance of batteries.

The invention discloses a preparation method and application of interpenetrating network gel based on bentonite minerals, and belongs to the technical field of collapsible loess improvement. According to the prepared bentonite mineral interpenetrating network gel (BT-PAA / PEG / PVA), bentonite serves as a crosslinking node and cooperates with a PAA ion network, a PEG flexible chain segment and a PVA rigid hydroxyl network to construct a triple interpenetrating structure, high water absorption, compression resistance, salt resistance and long-term stability are achieved, the gel is applied to collapsible loess improvement, and the collapsible loess improvement effect is good. And gel particles and soil particles are combined to form an anchoring effect, so that the permeability of a soil body is reduced and the soil body is prevented from collapsing.

The invention provides a biomass-derived spherical porous carbon material and a preparation method thereof, and a silicon-carbon negative electrode material and a preparation method thereof, and relates to the field of lithium ion batteries. The preparation method of the biomass-derived spherical porous carbon material comprises the following steps: carrying out pre-carbonization treatment on vinasse to obtain pre-carbonized vinasse, mixing the pre-carbonized vinasse with an acidic solution, and washing with water until the mixture is neutral to obtain pre-treated vinasse; mixing the pretreated vinasse with a pore-forming agent, a binder and water to prepare slurry, and performing spray drying on the slurry to obtain a spheroidized precursor; carrying out carbonization treatment on the spheroidized precursor; washing the carbonized spheroidized precursor with water until the spheroidized precursor is neutral, and drying the spheroidized precursor to obtain an intermediate; and activating the intermediate with water vapor to obtain the biomass-derived spherical porous carbon material. The material with a regular spherical and porous structure can be prepared, the material can be used for preparing a silicon-carbon negative electrode material with a stable structure, and the electrochemical performance of the silicon-carbon negative electrode material is improved.

The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.

The invention relates to methods for synthesizing an engineered adsorbent suitable for the selective extraction of lithium from brine solutions. The invention describes the advantages of introducing mixed metal oxides into the crystal lattice of anatase titania precursor. The invention offers significant advantages, including high adsorption capacity of the ion sieve, enhanced chemical stability of the sorbent, and higher lithium selectivity.

The invention relates to the field of batteries, in particular to a preparation method and system of a silicon-carbon material, and the preparation method comprises the following steps: pretreating porous carbon, conveying the pretreated porous carbon to a fluidized bed reactor, sequentially introducing a silicon source gas and a carrier gas for silicon deposition treatment, heating, introducing a carbon source gas, adjusting the flow of the carrier gas for carbon coating treatment, and discharging and cooling to obtain a finished product, meanwhile, reaction tail gas is recycled. The preparation system comprises a gas inlet unit, a fluidized bed reactor unit, a tail gas circulation unit, a feeding preheating unit and a discharging unit. The fluidized bed reactor comprises an outer shell, an up-down stirring device, a heat exchange assembly and an air distribution assembly, and efficient reaction and temperature control can be achieved. The silicon-carbon material prepared by the method has excellent electrochemical performance and is suitable for a lithium ion battery negative electrode material. The unique porous structure and the uniform carbon coating layer effectively improve the conductivity and the structural stability of the material, and meanwhile, the volume expansion effect of silicon in the charging and discharging process is reduced.

To provide a composition for chemical mechanical polishing and a polishing method that can effectively suppress contamination of foreign matters during manufacturing and can polish the surface of a semiconductor substrate to a flat surface.SOLUTION: The composition for chemical mechanical polishing according to the present invention contains (A) abrasive grains including silica and (B) a liquid medium, in the (A) component, when the peak intensity of 490 cm-1 derived from a 4-membered ring measured by Raman spectroscopy is x and the peak intensity of 800 cm-1 derived from a multi-membered ring measured by Raman spectroscopy is y, x / y is 4.5 to 6.0, and the (A) component has at least one functional group selected from those represented by the following general formulae (1) to (4), -SO3-M+ (1), -COO-M+ (2), -NR1R2 (3), -N+R1R2R3M- (4).SELECTED DRAWING: None

The invention belongs to the technical field of environmental protection, and provides a preparation method of an imine-modified functionalized mesoporous magnetic silicon dioxide nano material. The method comprises the following steps: synthesizing Fe3O4 magnetic nanoparticles in a Fe < 2 + > / Fe < 3 + > alkaline hydrolysis system through a coprecipitation method; then coating the magnetic nanoparticles with an amorphous silicon dioxide layer by taking TEOS (tetraethoxysilane) as a silicon source by adopting a sol-gel method, so as to prepare magnetic silicon coated nanoparticles; the prepared nano-particles are subjected to secondary silicon coating guided by a cetyl trimethyl ammonium bromide (CTAB) mesoporous template agent, and mesoporous magnetic silicon nano-particles are formed after calcination; and finally, carrying out surface amination modification on the mesoporous magnetic silicon nano-particles by utilizing an amino silane coupling agent, and then carrying out condensation reaction on the mesoporous magnetic silicon nano-particles and various aldehyde derivatives to construct imine bonds, so as to obtain the imine-modified functionalized mesoporous magnetic silicon dioxide nano-material. The imine-modified functionalized mesoporous magnetic silicon dioxide nano-material formed by the invention has the characteristics of efficient adsorption, rapid magnetic recovery and excellent environmental stability, and can effectively remove polystyrene micro-plastics and organic pollutants in a water body.

The invention relates to a silicon-carbon composite material with a porous structure and a preparation method thereof, and the silicon-carbon composite material with the porous structure comprises an N / P co-doped porous carbon skeleton with micropore, mesopore and macropore channel networks, and amorphous or low-crystalline nanometer silicon particles which are uniformly loaded in the porous carbon skeleton and have the average particle size of 15-40nm, the mass percent of silicon in the composite material is 40-60%, and good interface bonding is formed between silicon and carbon. The preparation method mainly comprises the following steps: firstly, preparing an N / P co-doped porous carbon skeleton through a template method in combination with high-temperature carbonization and N / P source co-pyrolysis; and hydrolyzing an organic silicon source in the carbon skeleton to form silicon dioxide, and performing low-temperature metal thermal in-situ reduction to obtain the nano-silicon loaded composite material. Through a unique porous carbon skeleton design and a precise in-situ composite strategy of nano silicon, the prepared material shows high specific capacity, high initial coulombic efficiency and excellent cycling stability and rate capability when being used as a negative electrode of a lithium ion battery.

The invention provides coal-based porous carbon for preparing a silicon-carbon negative electrode material as well as a preparation method and application of the coal-based porous carbon, coal-based porous graphite is used as a matrix carbon material, polymer resin is used as a rigid bonding and coating material, heterogeneous elements such as B, N and P are used as doping materials, a carbon nanotube is used as a flexible conductive buffer material, and the materials are dispersed in a solvent to form slurry; through atomization granulation and high-temperature carbonization, heterogeneous element doped resin hard carbon is bridged with carbon nanotubes to construct a three-dimensional rigid-flexible conductive network to cooperatively coat the surface of the porous coal-based graphite, and doped heterogeneous elements are utilized to induce chemical-physical auxiliary activation to perform micro-mesoporous precise regulation and control pore forming on an inner core and a shell. The prepared novel coal-based porous carbon is high in porous framework particle strength and reasonable in pore distribution and has a three-dimensional rigid-flexible conductive network core-shell structure. The invention aims to solve the problems of unreasonable pore distribution of porous carbon, poor matrix strength and the like in the preparation process of a novel vapor deposition silicon-carbon negative electrode material.

The invention relates to the field of battery materials, in particular to a preparation method and application of a high-rate silicon-carbon negative electrode material. The preparation method of the high-rate silicon-carbon negative electrode material comprises the steps of silicon powder pretreatment, silicon-carbon powder composite ball milling, phosphoric acid treatment, high-temperature carbonization and the like. The preparation method of the high-magnification silicon-carbon negative electrode material is simple in process and high in success rate, the cycle stability of a negative electrode is effectively improved, the silicon-carbon negative electrode material has the characteristics of low expansion volume and long cycle life, the phenomenon that a surface oxide layer hinders lithium ion diffusion is avoided, and the service life of the silicon-carbon negative electrode material is prolonged. The comprehensive performance requirement of the existing lithium ion battery on the negative electrode material is met, and the application potential is very wide.

The invention relates to the technical field of lithium ion batteries, in particular to a carbon source mixed gas CVD coated silicon-carbon negative electrode material, a preparation method and a lithium ion battery. The preparation method comprises the following steps: 1) preparation of a silicon-carbon material: placing porous carbon in equipment, regulating and controlling the gas speed and the dynamic rotation speed of the equipment to uniformly disperse the porous carbon, heating to 380-650 DEG C, and introducing silane mixed gas with the concentration of 5-50% to form the silicon-carbon material; and 2) coating the silicon-carbon material with mixed gas carbon: introducing mixed gas sources with different proportions into equipment, regulating and controlling the gas speed and the dynamic rotation speed of the equipment to uniformly disperse the mixed gas sources, and heating to 450-700 DEG C to realize uniform carbon coating on the surface of the silicon-carbon material. According to the invention, the problem of explosion caused by self-polymerization reaction of single acetylene is solved; and moreover, the uniform carbon coating isolates the side reaction problem caused by direct contact between the electrolyte and the nano silicon, and the stability of the silicon-carbon material is improved.

A layered oxide positive electrode material and a preparation method therefor, a positive electrode composition, a sodium-ion secondary battery and the use. The layered oxide positive electrode material has the following general formula: NaaNibCucMndTieMfOg, wherein M is a doping element, a=0.75-0.95, b=0.33-0.45, c=0.03-0.15, d=0.20-0.45, e=0.05-0.20, f=0-0.1, and g=1.80-2.20. In an XRD pattern of the layered oxide positive electrode material, the peak intensity ratio I(101) / I(003)=0.02-0.15, the peak intensity ratio I(101) / I(012)=0.35-0.47, and the peak intensity ratio I(101) / I(006)=0.08-0.57.

The invention relates to a fly ash-based MOFs adsorption-catalysis material integrated preparation method, and belongs to the field of solid waste treatment and resource utilization. The material takes industrial solid waste fly ash as a matrix, and is prepared by the following steps: firstly, carrying out alkali modification and silane coupling agent surface activation treatment on fly ash to form a high-activity matrix; then loading a metal organic framework (MOFs) on the surface of the activated fly ash through an in-situ synthesis process to form a porous composite carrier; the integrated material with CO2 adsorption and catalytic conversion functions is further prepared through impregnation of a copper-based active component and a high-temperature calcination process. According to the invention, the problems of high energy consumption, high cost and low comprehensive utilization rate of fly ash of the traditional CO2 capture and utilization technology (ICCU) are solved, high-valued resource utilization of industrial solid waste and efficient capture and conversion of CO2 are synchronously realized, and the method has dual values of environmental protection and economy.

The invention relates to the technical field of materials adaptive to extreme environments, and discloses cross-scale gradient co-doped multifunctional composite aerogel as well as a preparation method and application of the cross-scale gradient co-doped multifunctional composite aerogel. The multifunctional composite aerogel is co-doped with ultraviolet light-screening agent nano-particles, infrared light-screening agent nano-particles and functional nano-particles in a cross-scale gradient manner, and is used for performing selective filtration and full-spectrum regulation and control on sunlight penetrating through the transparent aerogel; the ultraviolet light-screening agent particles are titanium dioxide nano particles; the infrared opacifying agent particles are indium tin oxide nanoparticles; and the functional nanoparticles are silver nanorods. The composite aerogel provided by the invention improves the anti-ultraviolet performance and high-temperature heat insulation performance of the aerogel and provides a function of enhancing photosynthesis of plants, and meanwhile, the transmittance of the transparent aerogel in the visible light band of sunlight is not obviously reduced.

The invention provides hydrophobic silica wet gel, hydrophobic silica aerogel, and methods that can be used to form an enhanced hydrophobic silica aerogel sheet having an advantageous combination of properties. Some embodiments of the invention provide a hydrophobic silica aerogel having advantageous properties, such as desirable performance on visible transmission, haze, or both.

The invention relates to the technical field of solid waste resource utilization, and particularly discloses a waste incineration fly ash resource treatment method which comprises the following steps: firstly, efficiently removing dioxin in fly ash in a manner of adding a vanadium-cerium-loaded charcoal catalyst and co-pyrolyzing with fluidized bed combustion ash; the method comprises the following steps: preparing fly ash from fly ash, washing the fly ash with micro-nano bubble water containing carbon dioxide for dechlorination, adding an iron-manganese-silicon biochar adsorbent after dechlorination to adsorb heavy metals in the fly ash, sintering the fly ash after adsorption and fly ash under an alkaline condition to further stabilize residual soluble chlorine and heavy metals in the fly ash, and finally, recycling the residual soluble chlorine and heavy metals in the fly ash. And the treated fly ash and cement are processed into cement building blocks with good mechanical properties, so that resource utilization of the waste incineration fly ash is realized.

The invention discloses a silicon-carbon material as well as a preparation method and application thereof. The silicon-carbon material comprises nitrogen-doped porous carbon and an amorphous carbon layer coating the nitrogen-doped porous carbon, and pores of the nitrogen-doped porous carbon are filled with boron-doped nano silicon. The nitrogen-doped porous carbon improves the affinity of silane gas while improving the electron conductivity, a high-conductivity and high-density silicon-carbon composite structure is realized, the boron-doped nano silicon and the nitrogen-doped porous carbon form a nano heterojunction site, and the migration rate of lithium ions is improved, so that electrochemical reaction kinetics is improved, and the electrochemical performance of the lithium ion battery is improved. The material has the advantages of high rate and long cycle performance.

The invention discloses a gas-phase silicon-carbon negative electrode material preparation system and method, and belongs to the technical field of silicon-carbon negative electrode materials. According to the preparation system disclosed by the invention, the solid raw material supply device, the fluidized bed reactor, the vapor deposition rotary furnace, the product post-processing device, the heat recycling device and the gas raw material supply system are arranged, so that the problems of small production scale, high production cost and low production efficiency of vapor deposition equipment in preparation of the vapor silicon-carbon negative electrode material are solved; and after engineering amplification of the technology, vapor deposition uniformity is reduced, a filter is frequently blocked, and high-temperature sealing is difficult to realize.

An aerogel composite has excellent thermal stability even when exposed to a high-temperature environment, thereby being capable of maintaining high heat insulation.

The invention belongs to the technical field of silicon dioxide delustering agents for coatings, and particularly relates to a preparation method of silicon dioxide for delustering paint with elastic hand feeling, which comprises the following steps: S1, preparing water glass and a sulfuric acid solution; s2, adding cationic and nonionic aqueous dispersants and a silane coupling agent into water glass, and then adding sulfuric acid to form silicon dioxide silica sol; s3, carrying out acid-base regulation, heating and boosting aging, aging generation and other steps to generate precipitated silicon dioxide; and S4, washing the precipitated silicon dioxide with pure water, an ammonium salt aqueous solution and pure water in sequence, drying, and carrying out wax powder treatment and crushing through a high-temperature jet mill to obtain the product. The silicon dioxide for delustering of the elastic paint has the advantages of large pore volume, small bulk density, small particle size, uniform distribution and easiness in dispersion, has the advantages of good delustering property and good hand feeling when being used in the elastic paint, and is easy to industrialize.

The invention provides a preparation method of a hyperbranched polyimide-derived silicon-carbon negative electrode material, which comprises the following steps: S1, preparation of a carbon precursor: mixing 1, 3, 5-tris (4-aminophenyl) benzene and 4, 4 '-(hexafluoroisopropenyl) diphthalic anhydride for reaction to prepare hyperbranched polyimide; s2, preparing porous carbon; and S3, vapor phase silicon carbon deposition. The invention also correspondingly provides a silicon-carbon negative electrode, a lithium ion battery and an electrochemical device. According to the hyperbranched polyimide-derived silicon-carbon negative electrode material, the volume expansion of silicon in the lithium intercalation process is effectively relieved, the active material is prevented from falling off, and the cycling stability of the battery is improved.

The invention discloses a silicon / graphite / carbon-aluminum oxide composite negative electrode material and a green preparation method thereof, and belongs to the technical field of lithium ion batteries. Aiming at the problems of high volume expansion rate and poor cycling stability of a silicon-based negative electrode and high cost of a traditional process, the invention innovatively provides the following scheme: 1) waste photovoltaic silicon wafer ball-milling liquid and waste graphite are taken as core raw materials, and resource recycling is realized; (2) phenolic resin and chitosan are adopted as double carbon sources, a nitrogen-doped carbon layer (the nitrogen content is 3-5 wt.%) is formed through pH-induced self-assembly, and the conductivity and the Li < + > diffusion rate are synchronously improved; and 3) aluminum nitrate is introduced for pyrolysis to generate 2-5nm aluminum oxide for doping, so that the side reaction of the electrolyte is inhibited, and the volume expansion of silicon is relieved (the expansion rate is less than or equal to 120%). The preparation process comprises the steps of silicon / graphite dispersion, double-carbon-source compounding, ammonia water regulation and control precipitation and gradient calcination. Experiments show that the specific capacity of the optimized material under the current of 0.5 A / g reaches more than 800mAh / g, the 100-time cycle capacity retention ratio is more than 98%, the 1000-time cycle capacity retention ratio is more than 80%, the reversible specific capacity under the multiplying power of 3A / g is more than 550mAh / g, and the raw material cost is reduced by 40%. The invention has the advantages of high capacity, long service life, environmental protection and economy, and provides an innovative solution for the fields of power batteries and energy storage.

The invention relates to the technical field of polycrystalline silicon deposition used as a main raw material in the semiconductor or solar industry, in particular to a polycrystalline silicon deposition air inlet device based on growth characteristics of a silicon core rod and a control method. The control method comprises the following steps: determining growth abnormal area data of the silicon core rod and overall growth rate data of the silicon core rod based on the surface temperature distribution uniformity degree of the silicon core rod in a first preset time length and / or the growth uniformity degree of the silicon core rod in a second preset time length; determining to control air intake by a local control method or an integral control method based on whether the growth abnormal area with the non-overlapped area and the growth abnormal area after space splicing cover the silicon core rod for a circle or not and a comparison result of the integral growth rate of the silicon core rod and a preset integral growth rate; according to the invention, the control accuracy of the air inlet device is improved by improving the analysis accuracy of the growth characteristics of the silicon core rod.

The invention relates to the technical field of heavy metal recovery, in particular to a method for recovering heavy metal from metal waste. Comprising the following steps: preparing silicon-tungsten composite acid salt; preparing heteropolyacid powder; preparing a resin heteropolyacid composite material; heavy metals are recovered from metal wastes by a resin adsorption method. The silicon-tungsten composite acid salt is prepared under mild conditions through reaction of sodium metasilicate, sodium tungstate and potassium chloride, the operation is simple, the conditions are easy to control, the silicon-tungsten composite acid salt has rich active sites and a large specific surface area, the surface of the silicon-tungsten composite acid salt carries negative charges, and the surface of the silicon-tungsten composite acid salt is not prone to damage. Compared with a traditional chemical precipitation method, the method for extracting the heavy metal by using the silicon-tungsten composite acid salt does not need to add a large number of chemical reagents, and secondary pollution is reduced.